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Headscratchers: Back to the Future
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     Back to the Future 
  • The date indicator on the time machine only has room for four numbers for the year. So what if you wanted to go back to say, see the dinosaurs (i.e at least 65million B.C) you just can't go back before 0 A.D?
  • In the altered 1985 Mc Fly household why does everybody freak out - notably Dave ("why wasn't I informed?!") - when Marty inaccurately notes that dad wrecked THE car as if that would leave the whole family stranded? Marty certainly has his own super-cool ride as it turns out. Shouldn't Dave the businessman (who still lives at home) at least have his as well?
    • I think it's less that they're worried about the family being stranded as they're freaking out that there was a major accident with their property that nobody told them about.
      • Plus they could easily afford to rent a car for a few days, or take a cab.
    • If one of your family's cars got wrecked, would your immediate response really be "Oh well, mine's probably fine" or "Eh, we can rent one."?
  • How does Marty take a 1985 camcorder and hook it up to a 1955 TV system? Even if Marty brought cables, I don't think that TVs of that era had any inputs (besides the antenna). The Doc doesn't look like a A/V expert. The only way he could do that if he took apart the TV and used a soldering iron. What gives?
    • According to the DVD, the filmmakers couldn't even make that work. They tried, but ultimately put a new television set inside a 1950s model and tinted the footage black and white.
    • Don't forget, Doc's a Mad Scientist. If he can make a time machine, he can get a camera to work on a TV set.
    • Actually, Marty is the one hooking up the camcorder in a deleted part of that scene. He even asks Doc for an adapter that hasn't been invented yet, and somehow still manages to get the TV working correctly with just the parts from the lab. And an earlier version of the screenplay had Marty as an A/V whiz of sorts, so maybe it's a hidden talent of Marty's that the filmmakers didn't really expand on in the films proper.
      • On the other hand, the scene might've been deleted because the filmmakers realized how hard it'd actually be and decided to let the audience assume he had Doc's off-screen help.
      • In the 70's my family would ask me for miracles like this. Since my grandma had an early 1970's VCR with RCA inputs we could pull it off easily but without that you would need some sort of RF converter (common now...) or a camcorder with RF output and/or a 75->300ohm adapter (pretty common adapter back then actually) and I only saw one camera like that, and that one in the mid 80's no less, the rest were RCA output. Of course none of this even applies if there is something about 1955 TV's different from 60's and 70's TV's I was asked to do this on.
      • Marty is an aspiring professional guitarist. I speak from experience when I say that there are guitarists who wouldn't know an ohm from a dog turd, but are freaking whizzes at jury-rigging electronics. They kind of have to be.
      • Possibly Doc had previously modified that TV as part of one of his non-time-travel-related experiments?
      • I have a lot of experience with hacking TV sets, starting in 1967 or so (and working on sets going back to late 50s), and I don't really think Doc would have had much trouble adding a video input to a 1950s TV set. An old set like that would be a lot easier to do that to than a modern one as the needed connection point would have been a wire between two components, not a circuit board trace. And while the video timing was changed slightly from B&W sets to color, it didn't change that much; the camcorder's output would be well within the range of the TV's horizontal and vertical hold controls. Marty, though, could not have done it without Doc's help, at least not given what we see in the film. Maybe the "adapter" he asked for was to connect the camcorder to Doc's mod, Doc having already done the inside-the-set work.
      • To clarify the last comment: The 'RCA' signal format is essentially an electrical version of the over-the-air signal for TV broadcasts. It doesn't require any sort of conversion, it's what the tuner in the TV outputs anyway, before the rest of the TV decodes it. (Which is why the standard exist in the first place, to transfer signals between devices without having to convert back and forth to radio waves.) And color TV was explicitly created to be mostly backwards compatible with B&W, so that's not an issue either.
    • Funnily enough, this feat would be easier now than it was in 1985. My 2013 Casio EXILIM has a mini HDMI output. If I were concerned with making it work with a 50s era TV (antenna inputs), I would have a Mini-HD cable connected to an HDMI-to-RCA adapter to an RF Modulator to a matching transformer. All of these are readily available, due to concerns about backwards compatibility. They could have acknowledged this by having Doc ask Marty to bring the camera "and its connection adapters".
  • What the heck was Marty doing going over to Doc's garage at the beginning of the film, anyway? He can't possibly blame the fact that he was late for school on Doc's clocks— he was only there for a few minutes, and he was wearing a wristwatch.
    • He probably went by to use the speaker since Doc had said he'd be out, and spent more time there than we actually saw, maybe straightening things up and getting ready a bit, and didn't think to look at his wristwatch because he was surrounded by clocks that all said the same thing.
    • Marty also shakes his wrist on a few occasions after looking at his watch, implying it works poorly.
  • The first couple times Marty tries to tell Doc about the future (and the fact that he'll get shot), one thinks he ought to have been far more assertive.
    • Doc's just as stubborn and assertive about not wanting to listen. Plus, it's kind of a hard thing to broach with someone, especially a close friend — "Hey, you're gonna be gunned down in thirty years, I know because I was watching!"
  • Who the hell keeps their car keys in the trunk?!
    • Most likely, one of Biff's helpers must of swiped the keys from the top of the car and threw them in the trunk so no one could get him out.
    • Or maybe the band member who owns the car just set them down by accident in there and forgot to pick them back up. This troper's done that more times than he'd like to admit (fortunately, he always keeps a spare key in his wallet).
    • Or the keys were sitting on the bumper, laid there absentmindedly and they got knocked in when Marty was thrown into the trunk.
    • Older cars had trunks that had to be manually locked, and the car's owner didn't.
  • Marty could have traveled to any point in 1985. Why choose a point that was only eleven minutes before Doc got shot?! That wouldn't exactly be enough time to do anything about it even if he got there. Why not a day? When he got to 1985, he could have called Doc and told him.
    • It could be any number of reasons. Maybe some of that paradox talk actually seeped through and Marty was trying to interfere in events he clearly remembers (at least some of them) as little as possible? Maybe he was just in panic mode and went with the first idea that came to him. After all there was a lot going on at the moment.
    • Furthermore, had the De Lorean not broken down, it would be more than enough time to get to the mall, and pick up the Doc before the terrorists arrived. It would probably cause a huge paradox, as it would keep himself from travelling back in time, but that's probably what he planned on doing.
  • When Doc taped up the letter and found out what Marty had been trying to tell him all this time, why was a bulletproof vest his only precaution? A bulletproof vest won't exactly save you from getting shot in the head, so he's damn lucky that didn't happen. Why not get a gun or something?
    • Nevermind that even the best modern bulletproof vests are not going to stop even one 7.62 round at 5 times the range he got shot at. Even if he had some sort of phlebotinum vest he is not going to be able to sit up for a while.
    • He had a gun, but he threw it away when he was confronted by multiple men with assault rifles who weren't intimidated. And he probably wore a vest because he calculated it gave him the best chances of survival without tipping Marty off to its presence and thus causing a paradox. He probably reinforced the vest with metal plates or something and just took a chance they wouldn't hit him in the head.
      • More precisely his Colt Single Action Army jammed when he tried to use it. Then he threw it away. In the third film we see that he owned a very similar gun back in 1955 (probably owing to his fascination with the old West) if its the same gun and if it wasn't new to begin with that would explain why it breaks. As for the bulletproof vest its time to initiate protocol Willing Suspension of Disbelief. Most Hollywood films get the durability of these things wrong for the sake of telling a good story.
    • Doc might have built the vest. He's a goddamned supergenius, he can make a vest that stops assault rifle bullets.
    • As for the reason why they don't shoot him in the head: Most gunmen are trained to aim for the center of mass as it's the best chance for actually hitting something, let alone someplace vital. The guns they're using aren't too terribly accurate in the first place and a headshot, even at relatively close range, would be hard to make.
    • The ammunition they were using was probably substandard surplus as well. Notice how the rifle keeps jamming.
  • As Cracked.com pointed out, after crashing into the photo booth, the Libyan terrorists are still there, but we don't hear from them for the rest of the movie— or the rest of the trilogy, for that matter. What's up with that?
    • I always figured the crash killed them. Just because a car doesn't blow up doesn't mean its occupants are OK (and the photo booth was already on fire from the DeLorean's time jump, so even if they were just knocked out, they probably burned to death soon after).
    • Consider the fact that the van and it occupants were moving just under 88 MPH when it flipped over and crashed. Those two weren't going anywhere, at least not for a very long time, best case scenario.
  • How in the world did Marty manage to cross the wire at exactly the right second? Especially considering the problems with the car's ignition? Talk about catching a lucky break.
    • When lightning goes so slow you can see it crawl across the wire, hitting it at just the right moment is presumably not too hard. As for why lightning was slow, that's a good question.
    • Could be a Genius Bonus, actually. Lightning doesn't actually strike downwards from clouds to ground, it goes up from ground to clouds. Presumably the differential charge between ground and sky had been building up for a while, and was still waiting to happen when the time machine's hook hit the cable. Because the sudden contact between wire and hook created a better conduit for the electrical discharge than the clock tower alone, lightning that would've otherwise gone off an unknown number of seconds later instead took this path of least resistance immediately.
      • Well actually, lightning can go in either direction. But yeah, point taken.
  • Okay, seriously, what was the thing with Marty tearing a whole page out of a phone book just to get one number? And why was the café owner so blasé about it?
    • ... It's a page from a phone book. Phone books were and are replaced with relative frequency and weren't / aren't exactly rare or difficult to acquire, they usually fall apart quite easily anyway and it's hardly like he's holding up the place or planning the assassination of the president or anything; so who gives a shit?
    • The owner isn't blasé. He's actually pissed. When Marty first walks in, the owner is neutral. Once he sees that Marty has torn a page out of the book, he responds with an annoyed "Are you gonna order something?". The implication is that Marty had better do something to make up for the phone book he just ripped. As for why the owner wasn't more annoyed than that, he was probably planning to replace the book soon anyway. Phone books go out of date after awhile, because new phone lines are always being installed.
  • How did that bolt of lightning not kill Doc, gloves or no gloves? Not only did he survive, he practically no-sold it— he simply fell to the ground and got back up after a few seconds.
    • Because the bolt of lightning didn't go through him. Electricity is going to take the path of least resistance, and human bodies are actually pretty resistant. Given the options of going through a human body and through a metal cable explicitly designed and made to move electricity, electricity is going to go through the cable.
    • The "path of least resistance" business is a canard. Electricity takes all paths, the available current being divided between the paths, inversely proportional to the relative resistance of each. (e.g. if one path is 50 ohms and the other path 100, then the 50 ohm path gets twice the current of the 100 ohm path.) So even though the cable provided a nice low impedance path to ground, I'd expect some of the current to go through Doc. Funny thing, though: a lot of the people who are struck by lightning every year are not killed. Yes, it's a hella lot of current, but it's also very very brief. They aren't necessarily just fine, though. Mental problems are not uncommon in lightning strike victims.
      • And nobody's got mental problems like Mad Scientist Doc Brown. Many people seemed to think him rather odd in 1985.
  • Speaking of the bolt of lightning: Doc's tinkering with cables in the center of town, a policeman explicitly sees him, then a lightning bolt destroys the clock tower and sets fire to the road. How does he not end up in trouble over this? How can he justify it? "Weather experiment" doesn't quite cut it anymore after the strike happens.
    • When Doc says he has a "permit", he actually means a $50 bill (he bribes the cop), according to a deleted scene. In the same deleted scene, the Cop says something akin to "You're not going to set anything on fire this time, are ya doc?", indicating Doc's done stuff like this before and probably just paid for it (he has a family fortune, after all). Second, the fire trails are gone in a minute as evidenced by the end of BTTF 2 and beginning of BTTF 3.
  • What made Doc change his mind and go to 2015 instead of 2010?
    • He says right then and there that he changed his mind because he felt 30 years was a nice round number.
    • This troper noticed that he didn't "change his mind" so much as had it changed for him. He wanted 25 years in the future before Marty went through time and changed history. Part of the change was informing the past Doc that he is 30 years from the future. They shared a big adventure together and Doc succeeded in his project to get Marty back to the future. Upon seeing the "current" Marty and taking him home he was possibly inspired to have his own 30 year future jump.
  • Why would George want Biff anywhere near his wife and kids? He was a breath away from raping Lorraine the night of the dance. Even ignoring that he's still an asshole who is still physically stronger than him. He could come back anytime and get revenge.
    • George punching out Biff completely changed the power dynamic between the two. In short, after George laid out Biff, Biff was his bitch.
      • The point still stands, Biff still attempted to force himself upon George's wife. it's mind boggling that both George and Lorraine allowed Biff to stick around, specially after they had kids.
      • Biff was also a big stupid drunk kid at the time. Not saying that should excuse it, but it probably did a lot to mitigate it in George and Lorraine's minds.
      • Also, there's no back story given as to why Biff is still in their life at the beginning of the movie, but doesn't George work for/with Biff? Sometimes you really can't get rid of the bad people in your life, if you live in a small community.
      • Biff's a bully, not a prize-fighter. Once he got knocked out by George, he put George on his "people not to bully" list. As to 'why permit him anywhere near the wife and kids', don't forget that we're skipping over 30 years during which Biff treated George as the dominant male. Sometimes people can be forgiven for how stupid they were in high school, after a few decades.
  • In the end of the movie after Doc survives being shot at, he hands Marty's warning note to him and explains that "but then I thought...what the hell?" Ok, do he had that thought and then what? He'd torn up the letter and thrown it way, so how did he get it back?
    • Look back at the scene where Doc tears up the letter. The torn letter never leaves his hands or gets thrown away. He rips up the letter, then covers his ears when Marty starts to tell him about the Libyans. When the tree branch falls and disconnects the wire, Doc yells, "Great Scott!" Doc looks down at the fallen wire, up at the clocktower, and then (quickly) stuffs the letter fragments into his coat pocket right before he runs over to grab some rope. It's a quick sleight of hand, and you need to have a good eye to see it, but it's definitely there.
  • When Marty first enters the 1955 diner in the first film, his digital watch starts beeping and he has to hide it from Lou. So why doesn't he show it to Doc when Doc doesn't believe he's from the future? Doc can dismiss funny clothes, the picture of Marty's family, and Ronald Reagan as the President, but a high tech future watch would be pretty impressive.
    • Why is Marty's watch 35 minutes slow in the beginning of the film, and not just the clocks in Doc's garage? What the heck was he doing going to the garage, anyway? You'd think he'd be more careful about these sorts of things, having been late three days in a row prior to the film.
      • He wasn't careful for the same reason he'd been late the other times. He's a slacker.
      • Just before Strickland catches them, Marty tells Jennifer "This time, it wasn't my fault. The Doc set his clocks 25 minutes slow...." If you look closely, you'll see one clock that shows the time somewhere between 8:15 and 8:20, presumably as a "control" clock for Doc's experiment.
      • I'm not about to do the complicated research necessary (and I can just say "things are different thanks to time travel" anyway), but I just noticed that 35 + 25 = 60, so it's possible that the discrepancy between those two times is the result of a daylight-savings time transition in the trip to 1955.
      • Getting a tad off topic now, but it needs to be said; during the scene where Marty is filming Doc's experiment, he looks at his own watch and shakes it, as if it had stopped. He probably didn't notice that when he was going through Doc's garage earlier in the day.
    • I looked at the scene again and it appears that Marty doesn't have his watch on him when trying to convince the Doc he's from the future.
  • Did Marty remember to pick up the pieces of the letter Doc tore up that warned him about the Libyans before taking a passed out Doc Brown home in 1955?
    • In Part I, just after Doc tears up the letter, a limb falls off of the tree and distracts him from tearing it up further because his priorities are shifted to ensuring the cabling is still intact. You see him shove the pieces of the letter into his pocket when this happens.
  • The Marty we see at the beginning of the first film is vastly cooler than anyone else in his family and probably among the top 5% cool kids at school. He plays guitar, fronts a rock band, is an expert skateboarder, is dating someone who looks like Claudia Wells, and all the girls in the aerobics studio wave to him too. Now the running gag through all of the films is that everyone is like their parents and their parents are like their parents, but George and Lorraine are complete losers. How'd Marty-1 escape his destiny, even before he changed his past?
    • The thing he inherited from his father was his lack of drive and refusal to fight for what he thinks is important. Both he and his father are interested in creative works, but refuse to send their work out to companies out of a fear of rejection. As a result, Marty in the original timeline is implied to end up like his dad and take the route of least resistance, working a desk job or something instead of doing what he really wants.
      • Also a point in the second and third films: Marty's Berserk Button is calling him a coward or chicken. Someone does this and it blows his future.
  • How does Doc shift gears when the De Lorean is under RC control? While automatic was an option on the De Lorean, it's fairly well established that the one used for the time machine has a manual transmission seeing as Marty shifts into 5ht gear just before going back to 1955.
    • Close-ups of the shifter show it surrounded by wires. Doc probably rigged it and the clutch with small servos to do the shifting via remote.
  • How come Marty altering the events of 1955 changed the lives all the other members of his family, but not his? His brother and sister are very different from the ones in the original timeline, but Marty still has the same room, wears the same type of clothes (if he wouldn't, his family members should be surprised of his clothes, just like he was of his brother's fancy suit), dates the same girl, etc. All that changed for him, apparently, was that he got a cool car.
    • There's a theory that something did change for him. Notice how the "Don't call me chicken" Berserk Button doesn't exist in the first film, but is prominent in the second and third. The theory goes that growing up with an assertive father figure made it such that Marty felt he had to prove himself in ways he didn't when he had a pushover for a father.
      • I don't think there's any real evidence in the movies that changing the past changes the personality of a time traveller when he returns to the altered future, it's only the setting of his life that has changed. Regardless of how the past is changed, Marty and Doc remain the same as they were in the beginning of the first movie. It's true that the "chicken" Berserk Button doesn't seem to appear until the second movie, but on the other hand no one in the first movie calls Marty "chicken" or anything similar, so it's perfectly possible the button was always there.
      • Marty's young, and seems to be the most independent-minded of the family. He's apparently always sort of done his own thing, so it's not too surprising that with these factors he does change the least from bettered circumstances. To judge from the car the major difference is that his parents seem to appreciate his personality and are willing to reward it and encourage him. In the original timeline Marty was independent and outgoing in spite of his father, in the new timeline he's probably that way because of his father.
    • Suppose that he "adapted" as the new timeline went on (remember, he interrupted his parents' meeting, and it took him a full week for him to start disappearing).
  • Okay this has been bugging me for a while but, When Marty goes back to 1985, What was he exactly gonna do to save Doc cause he probaly assumes Doc didn't read the warning letter in 1955, And the Delorean stops and he sees the Libyans drive by and he tries to run after them. But if the Delorean didn't stop and he made it in time to Doc before the Libyans came, What would he do cause we clearly see the other Marty is there with Doc.
    • He would have gone to the mall as fast as he could, and screamed "The Libyans are coming!" so that Doc and his former self would flee. Of course, this would create a paradox. But Marty isn't really thinking about that.
  • The whole plan in the first movie is based on the fact that they know the exact time when lightning will strike the clock. One problem with that: the clock is two-handed and therefore cannot show seconds. The lightning could strike at 10:04:05, or 10:04:17, or 10:04:58, but they act like it will definitely happen at 10:04:00.
    • Just because the clock doesn't have a second hand doesn't mean that someone couldn't figure out from the internal mechanisms when it stopped.
    • Which would make some sense since minute hands don't 'tick' like second hands, they rotate smoothly, placing them only on the numbers at precisely the second the minute begins, otherwise they sit somewhere between the numbers, one could in theory approximate, give or take a couple seconds, the time to the second when the clock stopped based on how far the minute hand had travelled past the number.
      • Except that the clock tower clock clearly DOES 'tick' between minutes.
  • In the diner in 1955, Marty asks the guy behind the counter for something without sugar in it, to which the guy responds by giving him a cup of coffee. Marty then pays for the coffee with the loose change in his pocket, which came from 1985. Wouldn't the guy behind the counter have noticed something funny about that money? In 1955, dimes and quarters were made out of silver, not a nickel-copper sandwich like they were in 1985, and the two metals don't look the same. The proprietor should have suspected him of trying to pass off cheap counterfeit slugs.
    • The vast majority of people on the planet aren't going to stop and try to determine whether the random pocket change they were just given is the proper chemical composition. Seriously, when's the last time you actually looked at a quarter for any longer than it took you to determine, "Yep, that pretty much looks like a quarter"? If you've done it at all, it certainly wasn't while you were busy doing your job while other people are waiting to be served. The dude's a clerk behind the bar at a soda shop, not a forensic detective.
    • It could be that, by the luck of the draw, Marty happened to have been carrying change that came from 1955 or earlier.
    • In the novelization, he paid with a twenty dollar bill, which Marty explains away as just having fabulously rich parents. Since the novelization also contains a few quirks that were left out of the film, even the deleted scenes (such as a part with the terrorists discussing how to off Doc Brown), I'm assuming he gave him a single dollar.
  • Here's one more thing: the Twin Pines Ranch is where the Twin Pines Mall is 1985 (pre Lone Pine Mall). Marty drives long enough to escape Peabody and until the sun rises, and still has to walk a mile or two to downtown Hill Valley (as the sign indicates). This is all fine and good, but when he goes back to the future (crashing into the old Town Theater), he spies the terrorists rounding the corner and is forced to pursue them on foot. Not only does he get back not too long after the terrorists gun down Doc, but he managed to cover 2 miles or so in less than ten minutes?
    • He wasn't that far from town, and he arrived just before sunrise. Just before any time travel occurs, the destination time on the time circuits says 6 AM, and sunrise was 6:15 AM on November 5, 1955 in Los Angeles, and 6:26 AM in Fresno (which I presume is closer to "Hill Valley").
  • What would have happened if Biff was successful in breaking George's arm?
    • He probably would have trouble standing up to biff from then, Lorraine would have been raped, and George probably would have become even more afraid.
    • That's a faulty question. Biff wasn't trying to break George's arm, he was just holding him down.
  • We see the Mcfly's household in the improved timeline has a lot more money, no doubt because of George's new assertive attitude and powerful work ethic but it's mentioned that George just had his first novel published 30 years later. Does it say in the script what his new day job was? Was it freelance writer, or did he write for the Hill Valley times or something? I've never seen an explanation but I figured it was written somewhere.
    • I don't recall it being specified that it was his first novel, but I might be misremembering; he might only have gotten around to writing up that particular story by then. In any case, in the second movie the newspaper article outlining his death — chronologically published several years before the year the movie is set in — describes him as a local writer. Presumably he worked freelance.
  • I get why the creators essentially made Biff a servant to George in the end, but why in this timeline does Biff decide to go into a car detailing business instead of being a supervisor at whatever job they were both at in the original? What changed in him specifically?
    • Probably because he never got a job there in that timeline. Not everything has such an extremely specific reason. Biff is, all in all, a different person entirely in the new timeline.
    • I don't think he is a different person. Just afraid of George judging by how he turns out in 2015. He probably still likes to push people around and be the boss, he is the boss in the new timeline but since he is the only member of his business he can't order anyone around. So why would he wanna do it?
      • Because he wants to eat, pay bills and keep a roof over his head, and he probably likes working with cars if nothing else.
    • In the original timeline, it's implied he's the supervisor because he pushes George around to do all his work. In the new timeline, even if he's not less confident about pushing people around to begin with, since George isn't there to push around and do his work for him in the new timeline Biff's own incompetence is more easily exposed, and he doesn't become the supervisor if he even manages to get a job there to begin with. The butterfly flaps it's wings, and the ripples spread out.
  • Doc, having met him 30 years earlier, knows that Marty'll be accidently sent to the past if he invites him to his parking lot time travel experiment. Why doesn't he just not invite him and spare everyone the trouble? It doesn't make any sense that Doc would act the exact same way and do the exact same things in the 80s given what he learned in the 50s unless he WANTS Marty to be sent back.
    • If Doc doesn't invite him, he creates a paradox.
    • This may be a case of You Already Changed The Past. Notice how at the start of the movie, Doc urges Marty to be at the mall at a very specific time. If his plan was just to demonstrate time travel with his dog, then why would that time be so important at all?
      • Except as demonstrated repeatedly by all three movies, time travel does not work that way in BTTF. Doc has no knowledge that Marty "will" end up stuck in 1955 "before" Marty actually goes there and back again, and the new timeline overwrites the old one. We see that the old timeline developed as if Marty was never there (screwed-up family, Twin Pines Mall), so why would Doc be different?
  • Answering my own question here for the benefit of others: some may wonder why Doc pretended to be shot dead at Lone Pine Mall. Well, he probably reasoned from Marty's tape of the scene that his death has something to do with Marty going back in time. This turns out to be correct; Marty's entire motivation for getting into the De Lorean is Doc's death, which causes the Libyans to focus on him, thus providing Marty the need to escape. Had Doc not feigned his death, Marty would have no reason to go into the De Lorean, causing a paradox.
  • Uh Doc, don't you want to make absolutely, positively sure that time travel won't harm living creatures before you use your doggie-woggie to test your machine? Maybe send a lab rat or something back first instead of your beloved pet?
    • He knows it is safe and works, Marty told him so in 1955.
      • If he knew it was safe why send a dog instead of himself? He knows that time travel is possible, he presumably isn't certain how many tries it takes him to get it right. The fact that he's confident enough to send his dog speaks volumes.
      • Because he's making a recording of the experiment at the time in order to demonstrate to other people how it works. He needs Marty to hold onto the camera. He needs to be there so that he can tell people what's just happened so they don't assume it's a special effect or something. This only leaves one other candidate he trusts to actually get into the car and be the first being to travel through time — the dog. As for whether it's safe or not, let's face it — Doc Brown's a Mad Scientist with several screws loose, he's clearly not exactly big on proper OH&S procedure and probably just assumes it's all gonna be fine on the night. And in any case, as it turns out it is, so where's the problem? The time machine works and Einstein's perfectly okay, so no harm, no foul.
  • Why is the couple in the car, the first people Marty meets in 1955 after Peabody's family, so hostile/scared of him? He's just a kid in a life vest.
    • It's a radiation suit, not a life vest. Just a few scenes later, Doc himself asks "what on earth is this thing I'm wearing?" when Marty shows him the video footage from 1985. If a scientist can't identify a radiation suit, then it's doubtful that some old couple in their 60s or 70s can. Considering he's by himself in the middle of the road on a Sunday morning wearing this bizarre suit, it's understandable that the old couple would freak out.
  • One thing I never understood; Marty isn't in time to warn Doc before the Libyans shoot him, but luckily he read the letter and wore a bulletproof vest and survived. But even if Doc hadn't read the letter and was again shot to death, surely this wouldn't have mattered for one simple reason: Marty's De Lorean is still around at the time - the one that didn't just vanish - and, as we see at the beginning of the movie, Doc's plutonium supply is nearby; so surely, even if Doc had been killed, Marty could have retrieved some plutonium, put it in the De Lorean to power it, then gone back, say 30 minutes this time, and warned him properly?
  • As we learn in the second film, Doc Brown is a good enough scientist that he received an award for his work before the events of the first movie (Chronicled in the local paper, no less). However, both Lorraine and Strickland warn Marty against spending time with him. Strickland is something of a jerk, and could perhaps just not have a taste for scientists, but there's no real reason Lorraine would be so dismissive of the Doc.
    • He's still an eccentric weirdo; just because someone's won an award for science doesn't mean that they're necessarily a good role model for your kids to hang out with.

     Back to the Future: Part II 
  • How did Biff get SO powerful in 1985-A? Even if he was the richest person in the world it doesn't seem like he would be able to take over the whole city (or maybe even the whole state) without the federal government stepping in.
    • Money, Dear Boy. Biff hasn't literally taken over the city / state with an army like a warlord or anything, but he is hugely wealthy, and money buys influence. He buys off the cops so that they'll turn a blind eye to his crimes and he buys off officials to get them to do things that will advantage him and his business. As for the federal government, if there's one institution on Earth which is far from immune to the influence of extremely wealthy people with deep pockets, it is the U.S federal government. My guess is that Alt!Biff has donated quite generously to the campaigns of numerous congressmen, senators and Presidents over the years.
  • In the beginning of Part II, Biff sees the De Lorean take off and vanish into thin air, and is clearly baffled and disturbed by this. But the next time we see this version of Biff at the end of (which is chronologically one day later from his POV), he's being all nice and subservient to Marty like everything is normal, and doesn't seem to have remembered the flying car at all. Obviously everything by that point was already wrapped up with Biff's storyline, but it is a minor plot hole. They could have at least inserted a quick exchange such as "Say Marty, did you know that there was a flying De Lorean here yesterday?" And Marty could shrug or make up some funny explanation.
    • An unidentified flying object? People tend to look at you funny when you bring those up. And not believe you.
  • Granted, it would've taken away from the drama, suspense and humor, but in part 2, wouldn't it have been easier to take the Almanac from Biff the day after the dance, or just break into his house when he falls asleep?
    • I think they wanted it to be over with quickly, and probably didn't want to risk spending too much time on the task lest something go wrong (like, for example, Biff becoming onto them and taking greater security measures which would make it more difficult for them). Besides, since they already knew a lot about where Biff would be and what he would be doing during the time frame of the first movie, that gave them some knowledge as vantage ground.
    • It would be too late. Note that Biff took his first serious look at the almanac after the prom, and odds are, he'd be more than obsessive to keep it — or its valuable information — in his possession. He could've copied a few pages, hid them, and used them to become rich. It would be a bigger mess to solve if that was the case. It is not the almanac per se that Marty and the Doc need, but to prevent 1955 Biff from gathering too much information from it.
      • He brought the almanac with him to sporting events. In one of the articles where Biff wins big at horse racing, he's got the almanac in his pocket!
      • Just because he has it with him doesn't mean he doesn't have a "backup" in some form hidden somewhere. He easily could have hand-copied information from it and stashed it in a safe place just in case anything happened to the actual Almanac. Or for all we know, it's just another copy of Ooh La La with the Sports Almanac jacket on it.
      • Also, Old Biff told his young self to get a safe and keep it in there. Though this probably didn't occur to Marty or Doc before their mission (we briefly see 1985 Biff take the almanac out of the safe he eventually bought, which may or may not have been before he made his first bet).
  • Another example that would have taken away even more drama, suspense and humor by never giving 2015 Biff the chance to steal the Delorean in the first place: Marty and Doc could have stopped the police from taking Jennifer "home" to Hilldale; all Marty had to do was claim to be Marty of 2015, his thumbprint scan would have verified it, and surely the police would have left Jennifer in her "husband's" custody.
    • It was risky enough, according to Doc, for them to have been in 2015 at all in the first place, in situations where they might create a paradox by running into their doppelgangers.
    • And it'd be pretty odd for a visibly teenage Marty to just appear out of nowhere and give a thumb scan identifying himself as a 47-year-old man—especially since, if you look closely at Doc's newspaper, there's a bit in the newsline about "thumb bandits" (which are presumably the identity thieves of 2015). The police simply assumed Jennifer had gotten a really good facelift; to see her supposed spouse show up and appear to be the exact same age would raise some big questions.
      • Hold on then...What about Doc getting the procedure to look years younger? If he could do that, why wouldn't the police assume that Jennifer and Marty had both just done the same? Even if it's an expensive procedure that's not common for middle class folk or whatnot, there must still be a lot of people who would be willing to shell out bucks to look younger again.
      • It should be noted that for all Doc's hype about the procedure making him look years younger, he doesn't actually look any different when he finally reveals himself. Presumably the procedure doesn't work that well or is mostly hype; kind of like how skin creams which claim to take "years off" don't make you look incredibly different to how you did before you put them on. In any case, reverting an older man to a (slightly) younger man is different to reverting an older man to a teenager; it's presumably still not good enough to revert a 47 year old man to a point in his life where he was (presumably) still going through the latter stages of puberty.
      • Okay, but still: if Marty walked up to them claiming to be Marty Jr. Yeah, the thumb print would say he was 47, but since he and his father have the same name, he could explain it as a mistake.
    • IIRC, by the time Doc and Marty realize that Jennifer's missing, they're pretty much just in time to see the police officers drive off
      • No, you're not remembering correctly. Doc and Marty see the cops find Jennifer, ID her, and drive off with her.
    • It might have made the cops suspect that Marty tranqed her and left her in an alley. Even if he's her husband, that would still qualify as spousal abuse and Marty could be hauled off to jail.
      • But if they suspected that, they shouldn't have just taken her home (except insofar as the new lawyer-free, non-adversarial justice system may somehow disincentivize the cops to actually arrest people). And the suspected abuser showing himself to the cops would probably make him a little less suspicious. Although a hypothetically-abusive Marty might know that the cops would know that an abusive Marty wouldn't do that…
      • If he wasn't there, then they had no reason to suspect that she'd been abused and dumped in that alley for possibly suspicious reasons; they might just assume she'd gotten tanked and fallen asleep in the garbage. Her (much younger than he probably should be) husband suddenly showing up to nervously laugh it off and tell them that it was okay, he knew that his wife was unconscious in the alley for reasons he'd probably be a bit cagey about (since he's hardly going to tell them that they've both just travelled in time and she's been drugged because she was getting a bit too excited about it) is probably going to make them a bit more suspicious as to his intentions. Particularly since if she's unconscious in an alleyway, then he has no real reason to object to them helping her get home that probably isn't at least a little bit suspicious to a police officer.
    • What about this? When the cops drop Jennifer off at "home," Marty could have gone in and Doc could have stayed with the car. Marty could have just waltz in with the thumb key then explain the situation to Jennifer and haul @$$ back to the De Lorean. If at that exact moment, Lorraine and George showed up, he could pretend to be Marty Jr on his way to a date. If Marty Jr showed up while that was going on... um... HEY LOOK!!!
  • In part 2, Doc gets accidentally set back in time to 1885, he had the power necessary from the bolt, and he had the flux capacitor which was in the DeLorean, but he wasn't moving at 88 MPH ...What gives..?
    • Possibly the car span round so fast that its angular momentum was 88mph. Presumably the wheels didn't have to move that fast as the car was flying.
      • Since we don't know why the 88 miles per hour was necessary, no one can say for sure. Since the timecar always arrives at its destination cold, implying that it can absorb heat as well as direct kinetic energy, maybe the molecular motion of the lightning's heat was enough to make up for the lack of momentum?
      • Word of God says that it spun that fast, and that's why the vapor trails formed the reversed 99.
    • It's actually all explained in Doc's letter in Part III. The flux capacitor already had 1.21 jigowatts stored up, as Doc loaded the fusion generator prior to meeting Marty at the school. The extra power from the lightning caused an overload that scrambled the time circuits and caused the flux capacitor to spontaneously activate.
      • Gigawatt What the hell is a jigowatt?
      • An obscure way of saying gigawatt.
      • Of course, a watt is a unit of power not energy so you can't "store" 1.21 gigawatts. Presumably the capacitor had stored enough energy that it could discharge it at a rate of 1.21 gigawatts for however long is necessary to work it...
      • And that's ''exactly'' what Doc Brown has in mind! When he's despairing over where to find the McGuffin electricity, he talks to Edison's photograph: "Tom, how am I gonna generate that kind of power? It can't be done, can it?"
  • Why did Marty have to go to the future to prevent his son from taking part in the robbery? From Marty's point of view, the robbery wouldn't happen for 30 years. All Doc had to do was tell him exactly when it was going to happen, and in 30 years, Marty could prevent it without having to time travel.
    • Of course, Marty would have to remember this for 30 years. But surely he would remember something this important, no? Also, in the next 30 years, he could have just raised his son to be a bit less vulnerable to peer pressure and avoided the whole mess.
      • My theory is that this was all The Plan by Doc to improve Marty's life by having Marty choose to improve himself. Note that Doc doesn't mind actively telling Marty the mistakes his "son" will make, but he refuses to tell him a mistake that Marty will make; i.e., racing Needles because he called him chicken. The end of the third movie implies that once Marty changes, the future becomes a blank slate.
      • The only reason they go into the future to help Marty's kid is because that's how they ended the first one, and the ending was meant to be a joke. When the sequel happened, they had to start with the hook they'd already set up.
    • And of course, kids don't always do as you say. I guess Doc used a more method which would be easier to get result.
  • It surprises me that no one's bought this up yet. Gray's Sports Almanac. It was supposed to have the results of every major sporting event from 1950-2000. Did anyone think that book was just a little too thin to have all that history in there? A book with that much sports history in it would probably be the size of an unabridged dictionary! Plus, each sport would have to have it's own section. Baseball, football, basketball, hockey, boxing, horse races, etc. Never mind the fact that it wouldn't be just the results, there would have to be information such as MVPs, in-game and historical records set (and broken), expansion teams, and so on. Plus, we never really find out if ALL sports are covered in the almanac. Do the Olympics count? What about professional wrestling? MMA? Nascar? And what if some new sport was invented and implemented between 1950 and 2000? There would have to be a whole section on the creation of that sport, and then all the above information (MVPs, records, teams). And then in 1955, old Biff manages to open the page up to the exact game that's playing on the radio. I understand that it was easier to make the book thin so Marty could try and steal it later (and the mistaken identity when Strickland takes it), but couldn't they have come up with something else, like maybe a book that only detailed certain sports for the 50's only? Or certain sports only, like just baseball, football and basketball maybe?
    • The almanac could have been part of set. Marty might have only bought a volume with certain sports, either not realizing there were others or the shop didn't have them.
      • Indeed, only the set could have been organized a different way. The implication of the dialogue does * seem* to be that it's complete, though, and on the commentary track Zemeckis and Gale admit to the absurdity. Really, though, if it just contains the bare, basic statistics, which fill most every page in tiny print and in many columns, using lots of abbreviations, they could probably fit a hell of a lot more in there than it would appear by glancing at the cover and page number.
      • The first draft of the BTTF 2 script mentions that the pages of the almanac are super-thin, and that the almanac is composed of 5000 pages.
      • It's the future. They probably found some technology to make it small.
      • Or holographic in a controllable way, so that it's like several pages in one for each page. Or...something.
      • See, for example, Paul Atreides' copy of the Orange Catholic Bible given to him by Dr. Yueh: about palm-sized, but has thousands of pages. Has its own inbuilt magnifying device.
    • I just assume the shopkeeper (and the book itself) were exaggerating to make a sale.
    • Word of God: Bob Gale addressed this issue in the DVD commentary. The writers were aware that a book with that many years of stats for that many sports would probably be 50 times thicker, but they had to make the book thin enough to fit into Marty's pocket. Neil Canton hand waves it by saying "maybe it's just really small print."
    • Now, here's something to ponder. Isn't it highly possible that Biff's bets and his actions would probably eventually have a serious effect on the sporting world itself, and thus begin altering the actual results from the timeline that the book was from?
      • Then the results in the book would change, too, like the newspapers.
  • Why does Marty get blamed for the Sports Almanac fiasco? Isn't it at least partly Doc's fault for inventing a time machine that doesn't require keys or a password or at least some sort of security measure, and then leaving it completely unguarded? All Marty did was give Biff the idea.
    • Actually, it'd be more Doc's fault for talking so loudly - that other people can overhear him.
    • Marty didn't get blamed. He just declared that It's All My Fault.
    • It was kind of Marty's fault that Biff was able to steal the DeLorean from Hilldale, as he was supposed to be watching it whilst Doc was retrieving Jennifer, but instead wandered off looking at self-walking dog leashes. A split-second was all Biff needed.
      • Wanders off and leaves the door to the De Lorean wide open. Password be damned, if you walk off and leave your car door open you deserve to have it pinched.
      • Well, that's all in the past.
      • You mean the future.
      • Whatever.
    • Arguably, Marty is more at fault because he had greedy intentions when he bought the Almanac. Doc had more noble intentions when he invented the time machine.
      • So I guess Doc wanting to find out who won the world series for the next 50 years was just curiosity? I'd find it hard not to place a bet when I knew the outcome...
      • Probably; the guy sold his mansion and lived in a garage in pursuit of science and inventing time travel as a higher calling. Given that acquiring material wealth doesn't seem a big priority to him anyway, it's not hard to believe that he'd want to find out who won the next fifty World Series purely out of curiosity.
  • If Biff going back to 1955 created another timeline (and that's why going back from the alternative 1985 is useless unless they get things back to normal), how could he get back to his own 2015?
    • There is a deleted scene in which Old Biff fades away the way Marty almost did in the first movie. This suggests that the timeline was in the process of repairing itself to make sense. We know this can't happen instantaneously, or Marty would have started fading the moment he interfered with his parents' encounter. The scene was trimmed however, and we never actually see Old Biff fade away (although he does seem to be in pain upon returning).
      • He returned to the old time line because young Biff has free will, and until he decides to use the almanac the old time line is in place.
      • Time hadn't changed when old Biff left 1985, bit it had changed when he arrived in 2015 and was trying to repair itself.
      • Exactly - a later entry on this page (not mine) says more or less that the ripple effect doesn't fully kick in until a critical event's been reached; old Biff wouldn't be erased from existence until then. By time-traveling forward to 2015, he skips forward past the critical event and into a timeline he's no longer compatible with.
    • Zemeckis and Gale proposed that Biff did indeed return to 2015-A, which we saw on-screen after Biff returned, and which happened to be just that similar to the original 2015 for Marty and Doc to still carry Jennifer out.
      • Somewhere I read (DVD commentary? Novelization?) that Lorraine murdered Biff in 1996-A.
      • I figured it was the same reason they could leave Jennifer and Einstein in 1985-A; time transforms around them.
      • You're confusing effects that occur in time with effects that occur in metatime. When Biff used the almanac, and 1985-A overwrote the original 1985, 2015-A also overwrote the original 2015. Timelines aren't "parallel universes": only one version of a given time period exists at a given point in metatime.
      • How do you know how time travel "works"? Maybe there are alternate timelines coexisting, and the only reason Marty started fading out in the first film was that he was in the wrong one.
    • Also, the old Biff could meet the young Biff in 1955 perfectly comfortably, with neither of them falling unconscious or even the Universe imploding. Perhaps it is because the young Biff did not recognize the old Biff as being himself?
      • It's exactly because of that. The young Biff thought of the old Biff as "an old codger with a cane", and nothing more.
      • That, and young Biff was really dumb.
      • Exactly. Essentially a variant on Tricked Out Time with them avoiding the paradox through the power of dumb.
    • This troper wants to know how in the heck Old Biff knew how to use the De Lorean in the first place? He wasn't around when Doc explained it to Marty in BTTF.
      • Everything is labeled. You see, Doc is an Absent-Minded Professor, so I've no doubt he could lose track of what some of the buttons do.
      • Yeah, but how did he know to turn the time circuits on? And power up Mr. Fusion? And how did he figure out that he had to speed up to 88 mph to travel through time?
      • Maybe there's an Owner's Manual in the glove box.
      • In regards to powering up Mr. Fusion, the device was billed as a "home energy reactor", and probably a common household implement in the BTTF 2015. This doesn't explain how he knew about the other requirements to correctly operate the time machine, though.
      • Doesn't old Biff say something like "So, old doc brown finally made a time machine"? He's worked out it's a time machine, all he has to do is figure out the buttons. The time circuit panel with the date display is labeled, so he probably just kept pushing the buttons until he got it right. Given that he's 'from' the future, he'd know how to fly a hover conversion car.
      • As to knowing to accelerate and all, remember that he remembered seeing the car take off, accelerate, and then disappear back in 1985. He even notes it with "A flying DeLorean! Haven't seen one of those in... thirty years...?", planting the idea he remembers. Doc probably already had the time circuits on and Mr. Fusion powered up a certain amount... all Biff would have to do is punch in the date before flying off and speeding up.
      • And the digital speedometer says "Set to 88," a good indicator of the speed needed to initiate time travel.
      • Um, it's a time machine. He could have taken a month to figure out how to work it as long as he comes back soon after he stole it.
      • Except he would have had to figure out how it worked before he stole it. He didn't sit in it for a month in 2015.
      • You missed the point. Say he backed it away, spent a month in 2015 figuring it out, traveled back to 1955, then set the time circuits to return to 2015 a minute after he stole it. At that point, there's 2 Biffs and 2 time machines, and one of them drops off his time machine where he stole it, as we see in the movie, making Doc and Marty none-the-wiser.
  • In Part II, why are Doc and Marty in such a rush to get the sports almanac back on November 12, 1955? Since both have their past duplicates they have to avoid, it seems rather risky. Since Doc states they need to wait for Old Biff to give Young Biff the almanac, it's obvious they just need to get the almanac back sometime before Biff starts actively using it to bet on horse races, which he can't do until he's 21. Thus, they have several years in which to get it back, so why not wait until even just the next day to attempt to steal back the almanac? This way they wouldn't risk interfering with the events of the first movie.
    • Because Hell Valley Doc had been institutionalized, preventing him from building the time machine in the first place. The fading of the time machine would create a paradox so great that it would no doubt have a catastrophic impact on the universe. The only reason the time machine still existed was because the ripple effect had yet to catch up with it. Doc did not know how long they would have before before the time machine was erased. Every second counted.
    • Biff didn't need to be in possession of the Almanac to bet on sports events: he needed to know the results. If they had waited they were running the risk of him reading the book and memorizing certain results, possibly jotting them down, or even tearing out pages and hiding them somewhere.
      • I think you're giving 1955 Biff a little too much credit, he wasn't smart enough to try anything like that until several years later. Nevertheless it's still important to get that book away from Biff as soon as possible, there's nothing to stop him form placing smaller bets on other sport events illegally until he turns 21.
    • As Biff recieves the book, he's sceptical. We see Biff casually flicking through the book though, and the more he does so, the more he realises how important that book is. The longer they leave it, the tighter of a grasp Biff will have on it, the more he'll fight to keep it. Even by the evening he's swapping the covers to other books. The longer it's left, the harder it'll be to get back. At least on that day, they know exactly where Biff will be.
    • And all he has to do on November 13-onward to completely screw over Doc and Marty is to buy a safe or put it in a bank's safety deposit box or bury somewhere that only he knows about
  • In the first film, the DeLorean's exterior ices up after each trip through time. Why didn't that happen in the subsequent films?
    • Modifications made in the future, perhaps, although it does ice up in the Telltale game. It could have something to do with the ice not forming when the car is airborne, and it was hot enough in late summer in the Wild West in Part III that the ice wasn't noticeable.
    • Actually it does every time (though it thaws out relatively quickly). It's just not pointed out.
  • Why in the world would Doc have Marty take Jennifer out of the time machine and leave her in an alley? What, was she in his way or something?! Sometimes Doc is the dumbest smart person in the world.
    • She probably was in his way. There's not a ton of room in that car if you watch, Jennifer pretty much has to sit in Marty's lap when all three of them are in there. He probably got her out so that he could get out all the stuff he needed without risking groping his young friend's girlfriend in the process, and didn't think it was worth it to try and wrestle her back in when they only planned to be there for a few minutes anyway.
    • He had to take the car out in broad daylight to intercept Marty Jr. He probably didn't want to have to explain to people why he's got a teenage girl unconscious in his front seat.
    • Actually the Bobs never planned for a sequel so they had to have Jennifer in the car but never actually planned for her to do anything, and they were too lazy to actually write her into the story more so they knock her out because of Plot Convience.
  • What kind of place must Hill Valley be in 2015 that a gang could assault a teenage boy in a cafeteria without anyone uttering a word of protest?
    • Probably the same sort of place it was in 1955 where they did the same thing? Or the same sort of place New York is today? Most people don't want to step up and defend total strangers. (Especially nerdy white male strangers, who probably rank somewhere just above "big fat hairy bikers" and "people with flattops wearing very fashionable brown uniforms" for generating sympathy from onlookers.)
    • It's called the Bystander effect. This happens in Real Life all the time - you can have a gorgeous girl getting pummelled in broad daylight at a tourist trap. People will just sit back and watch.
    • It's worth noting that the folks on the cafe's stationary bikes start to get up after Griff tosses Junior over the counter, and Griff hollers at them: "Keep pedaling, you two!" I kinda thought the implication was that people wanted to help, but were too terrified by the psycho with bionic implants.
  • Interesting weather they're having in 1955: Immediately after the DeLorean gets struck by lightning and is seemingly destroyed, the storm ends! And then a few seconds later it starts raining down heavily, with no lightning!
    • That's not completely impossible under ordinary circumstances in real life. Also, in-universe, it may be the case that the storm was sort of "tugged at by causality", a la Rubber-Band History, with the purposes of aiding the time travel of both first-movie-Marty and second-movie-Doc.WMG 
    • Rainstorms often work like that; it's dry when the thunder and lightning happens, and then the heavens open. On a personal note, it's happening where this editor is currently sitting and writing right now.
  • So, if you meet a version of yourself from another time, you either pass out, or a universe-destroying paradox occurs. Why would you pass out? What's so shocking in seeing yourself? Sure, it'd be weird, but there are perfectly natural explanations, like it's your lost twin sibling or just an accidental double (I think I've heard somewhere that it's possible even between strangers), or somebody has assumed your appearence with cosmetic surgery for some reason.
    • Who said those are the only two options? All we really see is that's how Jennifer reacts. One data point does not equal a pattern or a standard or even a trend.
      • Doc Braun says that in rather no-nonsense terms. And Jennifer's reaction reinforces my point. Why does she pass out?
      • And Doc Brown then says, "That's a worst-case scenario." He doesn't say those are the only two options, he's saying those are the two far points on the 'bad reaction' spectrum. Jennifer passed out because she, personally, was shocked at seeing her older self. Not because passing out is the default response to anyone encountering their other self. This is evidenced by Marty and Doc Brown both running into their own past and future selves and nothing happening.

        All that happened was that Jennifer wasn't mentally prepared for it, and passed out.
  • How did Biff know how to operate the De Loreon? Only the Doc and Marty knew how to use it.
    • Pretty sure this is already answered elsewhere, but basically, the time-travel controls are ridiculously clearly-labeled and easy to use. Other than that, it's a car. Biff remembers from seeing it work in the past that you've gotta drive it nice and fast to make it travel in time, so he just gets in, sets the time, then takes off and floors it.
  • I know there's probably plenty of possible answers, but I think this every time I see the movie lately: under what circumstances would what's essentially a TV repairman call his customer a "chicken"?
    • Maybe he offered to hook up free premium channels for a bribe, and Chicken!Marty was scared of getting caught?
  • Why would Marty and Doc leave the De Lorean unattended, unlocked, with the keys in it? My car doesn't travel in time, I don't live in a high crime area and I don't even do that.
    • Doc left it with Marty. Marty got distracted and wandered off. Sometimes he's not that bright.
  • Strickland takes the almanac (actually just a porno mag with the dust jacket around it) from Biff. Did he not notice how the cover boasted statistics from years up to the next century?
    • He didn't take that close of a look at it at first - he just saw "Sports Almanac," and opened it right up to the porn. He didn't look at the cover much at all.
  • When doc and Marty arrive in 1985-A, Doc explains they cannot go back to the future and prevent old Biff from traveling to the past, cause they would be moving into that timeline's future, aka 2015-A. Yet earlier, Biff traveled to 1955, gave himself the Almanac (thus triggering the change in history), and was still able to go back to the original 2015. He does die, perphaps reflecting the fact that Lorraine-A killed him in 1996-A, but why doesn't the whole 2015 timeline collapse around Marty and Doc? This would imply the possibility of multiple timelines being able to coexist. And now the thing that's been bothering me: Doc and Marty take Jennifer from 1985 to 2015, then leave her in 1985-A before going to 1955 and restoring the original 1985. Doc says the present will restore itself around her, but this doesn't make sense if we take into account the existence of multiple timelines. You have just left 2 Jennifer's in 1985-A (supported by the fact that there is a Doc-A, in a mental institution, and a Marty-A, studying abroad) and no Jennifer in 1985, and seeing as the alternative timeline is restored, Doc basically killed Jennifer.
    • More to the point, how could the De Lorian be built if Doc is committed? That seems the universe-ending paradox right there. If there's no De Lorian, Marty never goes back in time and never comes back to the future or goes into the future. How would he have bought the almanac? How would he have even been able to go back to 1985A? ...This makes my head hurt.
    • This is why they absolutely had to get the almanac back ASAP—if they didn't, the paradox caused by the De Lorean not being made into a time machine would have caused the universe to implode. As to the OP's question, we don't know for sure it really was the original 2015 Old Biff went back to. Higher up the page it's theorized that 2015-A just happened to look a lot like the original 2015, and in fact Word of God says that he went back to the original 2015, and that the reason he died in the deleted scene was because time was changing around him as the changes he caused caught up with him. Ergo, he went back to the original 2015 because it hadn't changed yet, and after it did it had become 2015-A, not a parallel timeline. The reason it didn't collapse around Marty and Doc was either because it simply changed into the new timeline, or because when they left 2015 the changes hadn't arrived yet, but by the time they got back to 1985, they had. Which means that they left Jennifer in 1985-A and after they fixed things back in 1955, the changes rippled forward again and turned 1985-A back into the original 1985. So only one Jennifer, and she's safe.
  • Why did the paperback Gray's Sports Almanac have, or even need, a dust jacket? That's never really made sense to me at all, even as a joke.

     Back to the Future: Part III 
  • With all the talk about Doc wanting to destroy the De Lorean as soon as they got back, why was he so eager to then build a friggen time train?! What about all the talk about not wanting to mess with the timelines anymore?
  • Nobody in the Mc Fly seems to be bothered by how strange Marty was acting on the day he returned. Think about it from the Mc Fly's family perspective. He comes back home shocked too see his family almost like something major changed for him, (they don't know about their old selves remember) asking questions with answers he should clearly know about and falling over in shock when he sees his parents walk in the door. Maybe they could write it off as a vivid dream he has and that he was okay, but at the end of BTTF Part III not an hour later in their time he randomly shows up wearing a cowboy costume and loudly relieved that they were "Back to Normal". Even if they thought he was just really out of it from not sleeping too much wouldn't the new assertive George tell him to go to bed for another hour before driving or ask him why he is acting that way. True everybody has off days but Marty seems like he would be insanely out of it and might need to be cared for not knowing what we know. Why don't they seem concerned at all?
    • The McFly and Baines clans have a lot of nuts in their family trees ("Jailbird Joey"). Marty is somewhat normal by comparison.
  • Was there some kind of extreme climate shift around Hill Valley between 1885 and 1955? The Hill Valley of 1885 is a dusty little town with little vegetation, in the middle of hardpan desert that looks like it hardly ever sees precipitation. Yet in all time periods besides 1885, Hill Valley is often damp, with lush vegetation and prone to strong, drenching rainstorms. In 2015, there appear to be two strong rainstorms during Marty's visit, which was only a few hours long, which indicates more extreme climate change in a relatively short period of time. Yet, the most extreme change seems to take place early in the fossil fuel age, rather than later. What gives?
    • Evidently there was some very aggressive landscaping done in the intervening decades.
    • The suburb where Marty lives was also pretty clearly desert, or at least scrub bush land, in 1955 as well. Remember also that the first two movies are set largely in November (i.e. autumn, almost winter), a time of year which is likely to see a lot more rain even in the California desert, whereas the third movie is set in September (i.e. towards the end of summer), where there's likely to have been less rain overall.
  • So the De Lorean uses an internal combustion engine that Mr. Fusion doesn't work on. Why doesn't Doc just build an electric motor?
    • 1885 lacks the machinery and parts for him to do it in under a week. He says it'd take a month just to repair one broken part on the car when it blows out, remember.
  • Why was Doc just fine with being left in the 1880s, when he's usually so anal about altering the past? Also, why did he not want to bring Clara along with him into the future/present? She was initially supposed to die, so taking her along wouldn't have messed with anything, in fact it would've actually set things right by taking her out of a timeline where she shouldn't even be alive.
    • He is enough genre savvy to know that Marty ALWAYS mess up the timeline. Although he makes friends, none of them seems to be very close. About the Clara part, he met and fell in love with her for a span of four or five days, before Tannen killed him.
    • Well, we know he liked The Wild West anyway, so maybe he just figured that he could live out a quiet life in that era without disturbing anything. (Although he doesn't seem that keen to not disturb anything, befriending all the locals, becoming a major figure in town and all while using his real name.) As for Clara, I agree that that would be the most logical option. I can only assume the Doc's concern was that the culture shock would be too much for her.
    • If you remember, Doc told Clara the whole story and she didn't believe a word of it until she came across the model of the time machine in the stable. He couldn't take her back to the future because she dumped him. Also, on the subject of Doc not wanting to alter the past, III makes it clear that he's had enough of time traveling for personal gain, and has chosen to bury the DeLorean as a selfless act just so Marty can get from 1955 to 1985. When he wrote the letter he was happy living out his retirement in 1885, it wasn't until Marty found out that he got shot days after having written the letter that Marty went back in time and started changing things in a major way.
      • Presumably, Doc was too confused by his conflicted emotions to think straight. If he thought things out more clearly, bringing Clara back with him was the most logical choice (since she wasn't supposed to live in the past anyway). And convincing Clara would've been trivially easy if he had brought Marty and a few future artifacts to her house...
    • With Doc in 1885 you have only one person temporally out of place. With Marty there you have two. Which alters the past more? Which creates more danger of paradoxes?
    • And remember that Doc becomes a little less concerned about the Alteration of History by the end of Part I. That's why he decides to read the note and wear the bulletproof vest.
  • What the hell kind of Westerns did young Brown watch? That was the fruitiest cowboy costume I've ever seen.
    • Given his age, I'd guess black-and-white. The outfit wouldn't have been that bad in B&W (it was the colors that really got to me).
    • He was watching westerns that were made in the 30s, 40s, and early 50s. Check some out some time, and you'll find it easy to see why he thought that outfit would look right.
    • The novelization specifically mentions that his main source for ideas about the old west was Roy Rogers, who was a big T.V. star cowboy in 1955. Take a look at the getup he's wearing in his Wikipedia entry photo for an idea of what Doc had to imagine cowboys wearing.
    • It seems odd that Doc, who loves the Old West so much and is so intelligent, believes that people actually dressed like that back then. Then again, he could have learned all about the Old West after 1955.
      • He is exceptionally intelligent, but that doesn't mean that he has a comprehensive education about everything. The Old West may have been his favorite period of time from the movies he saw and he just liked it for that without ever getting around to doing historical research on it, especially since he was more focused on developing science. He built a time machine but that doesn't mean he's a historian... after all, he sets December 25th in the year 0 as the birthdate of Christ, which if you've studied the history behind theology is probably not the actual date of Christ's birth.
      • I just assumed that, despite knowing they were wrong, those clothes were the best he could get from the theme park at such short notice and he thought they'd have to do.
      • We surmised that people were exceptionally well dressed back in the day due to photographic evidence. Another view is that photography was a huge deal and time consuming, so they dressed up special for the early long exposures. When instant photography was invented, they still viewed it as special because it was a novelty that allowed even the lower classes to get pictures taken. So, even though criminals were getting mug shots taken, they were still opting to wear their finest clothes.
  • So a bunch of angry Indians are galloping away. Suddenly in front of them two loud, bright blasts occur, no doubt displacing a ton of desert dust. From the cloud a shiny silver object emerges, hurtling toward them... and they aren't fazed at all. How does this make any sense? Surely they'd at least try to get out of the way real fast?
    • Well they were running away from a US Cavalry charge at the time. What bugs me about the scene is how the Indians seem about to overtake Marty a number of times before mysteriously jumping backwards so that they don't.
  • In the third movie Marty and Doc are all in a hurry to get back to the future before Doc gets a bullet in his back, so they come up with the contrived and extremely risky plan of using the boosted locomotive. But when Buford is beaten they suddenly have all the time in the world. Why don't they go back to the drawing board and try to come up with some other way of getting the car to 88mph? Hell, Doc is a genius - given enough time he could probably hack up a steampunk manifold and refine existing gasoline, or some other suitable fluid or gas. But no, they proceed as planned, with all the problems that causes.
    • They tried to use whiskey as a fuel, but that made things worse. And had they had more time, they hypothesized pushing the car down a snowy mountain during the wintertime.
    • But after Doc was saved from the bullet, Marty got stuck facing off with Buford in a showdown, so then they had to leave before the showdown. Of course, considering Buford was sent to jail before they left, they could have pulled the plug on the whole thing at that point. Maybe since it was already the day at that point and they had everything lined up, they just thought "Ah... I guess we'll just go through with it".
    • Because Marty was probably getting a bit homesick by then. Time was still passing for him even if it wasn't from his family and girlfriend's perspective. He was also getting older, which would make it hard to go back after a long while without anyone being suspicious. There was also the chance that Marty or Doc would do something that would cause Back to the Future IV. They could easily die from something in the past. Buford could get out of jail seeking revenge. So basically, a lot of very good reasons.
    • At that point, Doc had resigned himself to leaving Clara behind in 1885, and didn't want to torture himself by staying near her any longer than necessary.
  • If Clara Clayton was supposed to fall into the ravine and, thus, have it named after her, how could Doc be survived by his "beloved Clara" in his obituary, unless there's another Clara we don't know about...
    • In the original timeline, Doc went to pick up Clara at the train station, meeting and falling in love with her there. When Doc never showed up because of Marty, Clara rented the buckboard and almost fell into the ravine.
      • This would explain why it was named the Clayton Ravine in the first place, but it seems like once we get a timeline where Doc saves Clara from falling in, it must have some different name. It's not technically a continuity error since Marty knew about the ravine before all this time-traveling happened, but I'm pretty sure I put more thought into this than the writers did.
      • There are three variations here. In one, Clara falls in and they name the ravine after her. In the timeline where Doc dies she didn't fall in, so they maybe kept it "Shonash Ravine". Alternately Clara may have thrown herself in in a bout of grief, so they rename it in her honor anyway. After the third movie it's thought that Marty fell in, so they name it "Eastwood Ravine" after his alias.
      • Yes. In the "original original" timeline where there is no Doc or Marty in 1885 at all, nobody volunteered to take Clara home, thus she had to rent that buckboard, thus she died, thus Clayton Ravine.
      • Word of God is that prior to Marty traveling back and saving Doc, Clara threw herself into the ravine in grief. That's why it remains Clayton Ravine up until the point he travels back in time to save Doc. So it goes like this: No Doc in the past, no Marty in the past, equals buckboard rental and Clayton Ravine. Doc in the past, no Marty in the past, star-crossed lover grief and Clayton Ravine. Doc in the past, Marty in the past, happy and saved Clara, Eastwood Ravine.
      • Except that what Word of God said in the official Gale/Zemeckis FAQ was that Clara might have thrown herself into the ravine, and thus the ravine might be called Clayton in that version of events or it might remain Shonash. They deliberately refrained from showing the name in those parts of the films because they wanted it to be open to interpretation based on people's own theories about time travel.
  • In the third movie, when the DeLorean is out of gas in 1885, why don't they take some gas from the earlier time loop version of the car that's still in the mine? (To avoid changing history, they could get some more gas from the future to replace it. Or just take an amount small enough not to be noticed; they only need enough for one trip.)
    • In the novelization Marty EXPLICITLY think about that plan, but Doc said that he had drained the De Lorean to avoid corrosion of the gas tank before storing into the mine. A pity.
      • Wordof God confirms that in the DVD commentary.
      • That's fine as far as it goes, but what did Doc do with the gasoline he drained? Don't tell me he just threw it away, or dumped it in the dirt. He's a scientist; surely he would have kept it around for his own experiments.
    • Also, in the film, before sending Marty back to 1885 Doc specifically says "I put gas in the tank," which implies that it was empty when they unearthed the car.
      • The whole reason why he wasn't able to get out of 1885 to begin with was an arrow ripped the fuel line and caused what was there (suppose it was a full tank) to leak.
    • Gas deterioates. And it's dangerous.
  • Doc's chemical bundles cause the locomotive's boiler to explode, yet despite the engine not being under pressure it's still accelerating?
    • Go back and rewatch. What does Doc say about his 'bundles' and the effects they will have on the train?
      • "Make the fire burn hotter, kick up the boiler pressure and make the train go faster" or "Each detination will be accompanied by a sufdden burst of acceleration"? The boiler had just exploded, the steam had escaped, there was no pressure to power the engine. No power, no acceleration.
    • The boiler hadn't yet exploded. It was venting steam like crazy, but you can still have pressure in a leaky container if it builds fast enough.
    • That wasn't the boiler that burst apart, it was the smokebox. The vapors seen escaping are smoke from the burning coal and bundles, not steam, which is why Doc and Clara weren't parbroiled on contact with them.
    • The boiler pops quite a few rivets, venting steam, in addition to losing the smokestack.
  • At the end of Part III we all see that not only is Doc living happily ever after with family, but he also created his very own Time Train. But in order to time travel, he needs a flux capacitor that requires 1.21 gigawatts of electricity. How was he able to create a flux capacitor with resources available only in 1885? He couldn't use the flux capacitor in the Delorean he buried in the mine, or else there wouldn't be a De Lorean in 1955! For that matter, what kind of power source is capable of 1.21 gigawatts of electricity that could be built with resources in 1885?! Even if we assume he got all the futuristic stuff from 2015, he still needed to rig a train that was capable of time traveling in order to reach 2015 in the first place!
    • A. Doc built the Flux Capacitor in the first place. If anyone knows how to build another one, it's him. As for the initial 1.21 gigawatts? Well, Doc might not know exactly when and where lightning's going to strike again, but he's a Mad Scientist. He could rig up a lightning rod and figure out how to channel it into a train at the right time. Also, chill. You're close to going over your daily allotment of exclamation points.
      • We don't know exactly how complicated a device the flux capacitor is - or Mr. Fusion, for that matter. It's possible that Doc could have built one or both from late-1800s components, given enough time (and, based on the ages of his children, it probably took at least a decade). Even if he can't create a fusion reactor, I suppose he could electrically connect the train's wheels to the flux capacitor, and then use a lightning rod to channel electricity into the railroad track. This wouldn't require exact knowledge of when the lightning was going to hit, or exact positioning of the train, as long as the train was traveling along the track at 88 MPH when it did strike. It might take several tries to get it right, but he'd only need to get lucky once.
      • Did you guys already forget he also had the hoverboard with him before Marty went back to 1985? You can never keep a good scientist down with resources like that mo'fo.
      • If it's true that the 88 mph speed is arbitrary, then Doc could have simply removed that, built the machine, attached a lightning rod on top, and waited inside during a thunderstorm. If he set his machine to go to 2015, he could then completely hover-covert it, install Mr. Fusion, etc.
    • It's time travel. He could cannibalize the flux capacitor in the De Lorean for his locomotive time machine...as long as he made sure to put it back (or replace it) before Marty retrieves the Delorean in 1955.
    • And why was everyone yelling in that scene?
    • Gesturing to the train, Doc explains to Marty and Jennifer, "it runs on steam!"
      • Also, a fairly large flux capacitor can be seen on the train's exterior if you look closely- it's much larger than the one on the Delorean. While it's possible the size of the flux capacitor has to be somehow proportional to the vehicle it's a part of, it might also be that size because Doc made it out of bulky 1800s steampunk components of some sort.
    • The other problem with all these theories is this: the whole reason for the third movie is that Doc explicitly said in his letter that he *isn't* able to fix the time circuits with 1885 components. Since he's in exactly the same situation at the end of the movie (stuck in 1885 with a De Lorean with broken time circuits still in the cave from before), what's different at the end such that he *is* able to figure out how to build another time machine? The fact that he has children when he arrives in 1985 means he had at least five years to work on it, so I suppose it's possible. You just think they'd give a better explanation than "it runs on steam."
      • There are two explanations:
      • Eh) Motivation: First time he ended stranded in wild west, he feels an old man, he likes the wild west, and fixing a Delorean Time Machine would be a huge effort which could end in too many changes in the timeline. But when he sent Marty Back to the Future he has a beautiful wife, a über-positive attitude to life, and the idea of a train to travel. So, when he feels depressed, he has his wife to cheer him up.
      • Bee) Plot: If he could fix the Delorean or make a Time Train when he put a foot in 1885, there would not have been Btt F-3. (Hey! I'm Doc Brown. I will build a Time Train, go to 2015 and buy some replacement parts, then back to 1884 just when I arrived first and give me a letter: "Hey Doc, I'm Doc. I built a steampunk time machine, went to the future and buy this parts for you. Don't forget: go to the future, buy these parts and give them to yourself with a copy of this note and then go back to 1985 for Einstein. I do this to avoid messing with the timeline. Hehehe, we are a pair of genius... PD: Take care of your teeth, I got a caries and it was YOUR fault."
      • Also, Sea) Marty: While we know that it would be possible for Doc to fix the Delorean, he didn't know that for sure. He might have run into a problem that even he couldn't fix, or he might have just died before finishing it, either of which would have left Marty trapped in 1955. 1885!Doc no doubt felt responsible for Marty's predicament, and he knew that 1955!Doc would have a much easier job. He took the option that would give Marty the best chance of getting his hands on a working time machine.
      • The first time Doc is stranded in 1885, he doesn't really mind. He's done with time travelling and thinks life in 1885 is better than life in 1985. Also, suitable replacement parts won't be invented until 1947. He could invent those, but who knows how many early-20th century inventions he needs to do before he can make those? So, he decides that it's easier to stay in 1885. But Marty needs to get home, so he buries it in the mine until 1955. Note that Doc has done some inventions in 1885 to make life easier: he's invented a fridge. By the second time he gets stuck in 1885, this time with Clara, he's realised that 1885 is a dangerous place (Buford Tannen will be released from prison someday, and then what?). Perhaps Clara and the kids would like to see too how 1985 is. So Doc starts building this new time machine, which takes him years, looking at the kids' ages. I guess that after a while, he did get a little homesick about Marty and 1985. So, Doc goes back to the future.
      • There's another explanation, one that is clean and simple, and really doesn't require anything more than what we see in the movie. When Doc said that he couldn't repair the time circuits, he meant that he couldn't do it at a scale such that the DeLorean could actually carry it. Look at what had to be done to the Train to get it to work as a time machine - there's no way that a small car could carry so much. It wasn't until he had the inspiration of using a train to generate the required speed, thanks to the events leading up to Marty's return to 1985, that he realised that there was a way to make time circuits for a time machine in 1885.
      • Another alternative is that the DeLorean had redundancies in its time circuits, in an attempt to prevent being trapped in the wrong time - the redundant circuits were fried along with the originals, unfortunately, but they were both repaired by 1955 Doc. As the DeLorean was to be destroyed upon return, Doc had taken the extra circuits out, in case of some unfortunate accident. Less likely than the size explanation, and requires some extra speculation, but plausible.
  • How could Doc Brown and Clara have a healthy kid at their age, let alone two? In the first film, 1955 Doc even says that he's amazed that he's going to be that old. So how is it possible for that to happen?
    • Men don't stop producing semen due to old age the same way that women undergo menopause. Doc's age is irrelevant— only Clara's. And she's considerably younger than he is.
    • Not to mention, In Vitro Fertilisation or some other advanced form of fertility aid would have been available in 2015 or whenever they went to the future.
    • Mary Steenburgen was only 34 when she made BTTF III, so it's likely that her character was somewhere around the same age, still perfectly within the normal age range for having a child. Second, Doc did go to a Rejuvenation Clinic before picking up Marty at the end of BTTF I. Maybe the reproductive system is covered as part of the "total overhaul" Doc said. Although again, men never really lose the ability to have kids (there are men today who have had kids in their 70s, 80s, even 90s, though with much younger women, naturally).
  • Since doc stays in 1885, how does he get away with stealing and wrecking the train?
    • The only witness saw him with a scarf over his face. They didn't exactly have CSI's back in the 19th century to link him to the crime.
  • When 1955 Doc saw his tombstone, how come 1885 Doc didn't remember it?
    • Because that Doc never saw the tombstone, in the same way that the Doc from the start of the first film didn't remember meeting Marty in 1955.
  • So, Doc couldn't repair the time circuits with 1885 components. But he knew how to fix them with 1955 technology; couldn't he build the components he needed? He was able to build a steampunk ice-making machine, would it be that difficult to build 1955 circuits? I don't have knowledge of these things, so probably my question is stupid... but why is it impossible?
    • Because making refrigeration coils is considerably easier than making something to produce a vacuum and thus vacuum tubes, which are clearly a part of the 1955 "microchip"?
    • Pulling a vacuum isn't that tough (see Magdeburg Hemispheres, 1656). But decently working vacuum tubes are tougher than you might think. Glass-to-metal seals (so the connections can get out without letting air in), some fairly exotic alloy coatings on the elements to improve emission from the cathode and reduce secondary emission from the others... even if Doc knew all about that, he wouldn't necessarily have access to the raw materials in a small settlement in the Old West. Then there are other parts like resistors and capacitors... maybe hundreds of feet of magnet wire for transformer windings... all this stuff took a lot of incremental development to get, even to 1955 standards.
    • He does, eventually, to build the time train.
  • Okay, Doc has somehow made a refrigerator that fills an entire room. Why is he filling the thing with original Hill Valley water? Surely he can build some filters or an evaporator/condenser into the thing to purify the stuff he drinks. Heck, the thing appears to be steam-powered, so why can't he capture the steam coming off the boiler and drink that?
    • He still has to get the water from somewhere, so he probably figures it's easier to just use the most conveniently available water source. Plus, he probably doesn't want to have to spend ages filtering it, purifying it or collecting every evaporated drop every time he just wants a quick drink. Besides which, he presumably had to live on the local water supply before he got the refrigerator up-and-running, so it's likely he simply got used to the taste, or even likes it.
  • Was anyone else disappointed that Old West Doc hadn't acquired a new dog back then, and named it Newton?
  • The engineer in Part III tells Marty and the Doc he can get the locomotive up to 50 fairly easily, and that 70 isn't out of the realm of possibility. Why did Doc throw in his doctored logs when the train was only going 20?
    • As Doc pointed out, they were based on a chemical formula designed to "kick in" one by one - presumably their exposure to heat over time starts the chain reaction that increases the boiler pressure sequentially, so throwing them in later would actually be counter-productive as the train wouldn't get up to speed before plunging over the ravine with them both inside the DeLorean. Of more concern is why Marty didn't give the Doc the hoverboard in the first place to prevent him having to make a very dangerous jump from the train to the DeLorean.
      • Perhaps it's also an example of the writing staff showing their work. Many American railroad tracks, in the period which the movie is set, were built hastily and to very low quality standards. Trains often moved slowly not because of technical limitations,but because the track was so poor that they could derail at higher speeds. Doc might have realized that the more time the train spent around 88MPH, the greater the chance that the train would crash and the whole plan would fail.
      • Ah, but once the train hit 88MPH, the time machine (with them in it) would leave that time frame and the fate of the train wouldn't matter. You're just not thinking foutrh-dimensionally.
      • You're not thinking third-dimensionally, if the train derails before they hit 88 MPH because it accelerated too quickly what good is that?
    • They only had a certain amount of track before they reached the ravine. It's best to accelerate as fast as you reasonably can.
  • Marty and the Doc end up with a photo of an empty burial plot. So what would happen if Marty or Doc (or someone else) went to the 1955 graveyard and spied on Marty and 1955-Doc digging out the buried DeLorean? What would cause Marty to return to 1885 to save Doc?
    • I presumed Doc set a false tombstone to maintain the timeline.
      • Then the post-ripple photograph would have been the false tombstone, not an empty burial plot. A bigger question is why would the burial plot be empty after 70 years in a cemetary? Wouldn't someone else have been buried there by then?
    • Same reason why Jennifer still has the piece of paper that read "YOU'RE FIRED!" before the timeline changed, and why Marty still has the photo of him and his siblings in the first film: they're immune to the Ripple Effect.
    • Doc at one point says the picture represents what will happen with regards to the confrontation with Tannen. It's essentially become not just a picture of a plot of land, but an artifact representing the potential outcomes of time travel. Thus why it fades out completely when the confrontation is resolved without anyone dying. There might actually be someone buried there now, but the photo didn't need to show it because it's not relevant to what the photo is now.
    • That timeline doesn't exist anymore. The movie doesn't say, but there are an additional timeline: Martys timeline, the one the movie follows. While 1955 Doc and Marty finding the tombstone exists in Martys timeline, spurring him to save 1885 Doc, it doesn't exist in the common timeline. It is pointless to try and figure out what would happen in another timeline as a result, since it doesn't exist, anymore.
  • The DeLorean that Doc came to 1885 in should still be in the cave. right? Surely, there should still be some gas in there. Even if it's all evaporated, couldn't he leave a note in it that says "Marty, put a can of extra gas in the trunk. Trust me on this. Thanks."?
    • Doc wouldn't mess with the car in the cave unless there was no other alternative because even the slightest mistake could alter the timeline.
      • Go to post office, ask for your letter back, add a little addendum, give it back to the post office.
    • The gas tank also received a nice, big hole in it. Materials and tools for a proper patching job wouldn't be available for decades, and a makeshift one wouldn't be reliable.
      • This is grasping at straws. You really don't need much to fix a hole in a watertight, non-pressurized vessel.
      • But even then, there's the gas tank on the DeLorean in the cave that's still good.
      • Gasoline has a shelf life. Even 1 year old gas will cause lots of problems.
      • And, conveniently, Marty goes back to about nine months after Doc arrives in 1885. By then Doc would have already prepared the De Lorean and buried it in the mine. Even if he had kept the gasoline when he drained it, after nine months stored in an 1885 container it would be ruined as fuel or evaporated, or both.
      • There'd be no gas in the buried DeLorean because, as any gearhead will tell you, when you put a car into long-term storage, you have to drain all fluids from it. Especially gasoline, because it will corrode the tank. Also, in 1955, the 1955 Doc says to Marty "I put gas in the tank", so it was already established that there was no gas in there.
  • If Doc knew the risks of time traveling and changing the time course since 1955 then why did he decide to stay and live in 1885? Isn't that a highly risky way of changing the time course too?
    • It is, but in Doc's mind it was less risky than the only other option of having Marty come back and try to rescue him. Doc figured that he could manage his own influence on history by being as low-key as possible. As far as the other residents of 1885 knew he was just some old blacksmith who lived in his workshop. Marty coming back for him introduces a whole lot of new variables and Doc was afraid it would only make things worse than they already were.

     Back to the Future: The Game 
  • In the Telltale game, the timeline eventually gets so messed up that the events of the movies never happened, up to and including the part about the time machine having been built in the first place. Shouldn't that cause a major Grandfather Paradox, making that version of the timeline unviable?
    • Delayed Ripple Effect works on time machines as well as time travelers.
      • Also it doesn't actually no longer exist, it still can be recreated! Plus the ending of the three games shows it still does exist.
  • Couldn't Doc and Marty just kill Edna in 1931 instead of having to go through a long sequence that leads to the planned break-up?
    • Right, because Doc and Marty are cold blooded killers who would be totally fine with straight up murdering someone. That's completely and totally consistent with their characters.
    • The timestream would also take a way bigger hit if they did that.
  • Also, why doesn't Marty just swap Emmett's mind-map with Kid's? Surely Kid must be a "Degenerate Criminal", and Emmett didn't even test Kid's mind-map when the break-up was about to happen. Why go through such a long sequence involving changing smells?
    • Maybe the punch card had some kind of identifier we couldn't make out printed on it. So switching them wouldn't work because Edna would have noticed, being the one to get Emmett to build the thing.
    • If you click on Kid's card, Marty examines it and notes that Kid's name is written on the card. Why you couldn't just get a blank card and punch holes in it to match Kid's is beyond me though.
  • In the third episode, Einstein and Doc disappear from the Delorean wreck and we only see their alternate universe personas. But Marty never changes to his alternate personas throughout the series. Why does this affect Doc and Einstein, but not Marty?
    • Because Doc isn't Doc anymore. By going off with Edna instead of going to see Frankenstein, he is essentially preventing a fundamental aspect of his own Doc-ness. The moment he displays the mind map thing instead of the flying car, he stops being Doc Brown, and starts being First Citizen Brown. It just took until Marty hit 88 for the timeline to catch up to him. Marty didn't disappear because: a.) He didn't put his own existence in jeopardy, and b.) even if he had, it would have taken the timeline longer to catch up to him (due to being the last born), which gives him a chance to undo the damage.
  • In the Telltale game, if the DeLorean was duplicated when it was hit by lightning and the duplicate was sent to a dystopian 2025 where Griff Tannen momentarily took possession of it, was Doc, who was inside the DeLorean at the time, also duplicated? If so, what happened to the duplicate? Did Griff kill him?
    • One episode is named Double Visions, and in the log in screen to play the game, you clearly see Doc, as the figurehead for that episode. Not that I have been the future or nothing, but I think this will be explained soon.
    • Why would the duplicated DeLorean have been sent to a dystopian 2025?
      • The lightning bolt sent the original seventy years into the past, the duplicate went seventy years into the future.
      • I think the above editor was questioning the "dystopian" part. There's been nothing to indicate that 2025 will be any worse than 2015.
      • One could only assume the future episodes will explain that part. The original 2015 no longer exists as of the end of the third film though either way.
      • I have a feeling that the "dystopian" reality is the one we see in Citizen Brown. I have a feeling that Marty will get help from Doc's duplicate in Double Vision.
      • He didn't. But maybe he'll pull a Past Max in Episode 5.
  • Telltale game again. Episode 3. When Marty finally gets in to see Citizen Brown, the latter shows him a picture from 1931 of Kid Tannen's arrest, and the former points out himself and the "real" Doc together in the gazebo in the background. If everything that's ever been established about photographs and time travel in this series is reliable, Doc if not both of them should have faded from that photograph long before Marty ever saw it!
  • In the Telltale game, the chain of disastrous alterations to the timeline starts with Marty going to the 17-year old Emmett Brown for his rocket drill, but all of that was completely unnecessary. The DeLorean was fully functional at that time, so why did Marty not just hop in and go to whichever point in time he needed to to get the tools to bust Doc out of jail? If there's nothing useful in Doc's lab in 1986, then jumping to 1955 or later and talking to a version of Emmett Brown who's already aware of time travel would be infinitely safer than pestering a teenager who hasn't even really decided to be a scientist yet. I get that this doesn't occur to Marty, who has trouble thinking 4-dimensionally, but why doesn't Doc think of it?
    • And if that opportunity was missed, then Marty could still have avoided involving Edna, effectively ending the game at Episode 2, if he'd just jumped to, say, 1989. Since the Marty of 1989 would be 21, he could just walk into a liquor store and buy the alcohol. This is of course assuming he has a form of ID on him that will work. This troper is not familiar with American liquor stores and the kinds of ID they take.
      • Marty's driver's license would be expired, but it would still have his date of birth on it. If the clerk at the counter was laid back enough he could probably still accept it since it's still proof that he's 21.
      • They're also in the middle of the prohibition. Alcohol is illegal. Other than Young Emmett, Marty's only other option is Kid Tannen.
  • In Episode 5, why didn't Marty tell Alt!Doc that his plan to get his younger self and Edna back together by making his younger self no longer interested in science, which in turn would cause the time-traveling De Lorean to no longer exist, cause a paradox? A universe-shattering one?
  • When does this take place in Doc's timeline? The De Lorean still exists, there's no time-train, and Clara, Jules, and Verne aren't even involved. The De Lorean does have the hover conversion and Mr. Fusion, but wouldn't Doc have gotten those when he heard that Marty Mc Fly Jr. was thrown in jail, and thus rushing back to 1985 to tell Marty?
    • This is after the third movie. Marty actually asks Doc about how he rebuilt the De Lorean and Doc replies that the lightning bolt that struck the car in 1955 created two copies of the car, one went 70 years back to 1885 and one went forward to 2025. This De Lorean is that one. He also mentions Jules, Verne, and Clara. Some of the dialog leads me to believe a considerable amount of time has passed. This would make sense as Doc had had some treatments done on his first trip to the future that added decades to his life (so that Christopher Lloyd could play the character without wearing the Old Doc makeup.) but Doc's mention of the visit he had planned to 2011 suggests that this character has aged back to where he is now to account for Lloyd sounding 25 years older.

     Back to the Future: The Ride 
  • How does 1955 Biff know how to operate the DeLorean?
  • Since the ride could fit into the trilogy's continuity, how does 1955 Biff not remember his escapade through 2015 and the Ice Age?
  • Why is the clock on the Clock Tower in 2015 working? Isn't it supposed to be still broken even after 60 years.
    • The ride takes you 4 days after the events of BTTF Part II to Oct. 25, 2015. Is it possible, with the way things work effeceintly in 2015, that it was rapidly fixed or replaced within that time?
  • How is the DeLorean still there? It was destroyed at the end of Part III. Did Doc Brown simply rebuild one prior to the "8-seater" DeLorean?

    Paradoxes 

  • When Marty goes to 2015, how does he meet himself? Think about this: when Einstein (the dog) goes one minute into the future, does he meet up with future Einstein? No, because there is no future Einstein. Einstein just skipped over that minute, and for one minute there was no such thing as Einstein, anywhere in the world, until the DeLorean showed up again. The only way time-traveling Einstein could meet a future version of himself is if he went back in time and then caught up with himself via The Slow Path. Similarly, if Marty jumps to 2015, there should be no future Marty to meet. Logically, Marty went missing back in 1985, and there was an unsuccessful search and eventually he was presumed dead etc. (which would be rather dark, actually...). The only way Marty can meet himself is if he meets a version that has already been to 2015 and back. This brings up an interesting theory: maybe future-Marty knew everything that was happening behind the scenes, but didn't bother involving himself because of the Temporal Paradox or something.
    • This is actually played straight in Flight of the Navigator where a boy is picked up by an alien spaceship and dumped 8 years into his own future by accident. History recorded that he went missing once he was removed from his own timeline. Once he managed to return from the point he left, the timeline continued on as it should have with him in it.
      • Actually all one has to do to explain it all is that Marty could obviously conclude that the future he travels to is part of a current timeline where he did travel back to his own time and lived out his life, thus being able to meet his future self.
    • Regarding both the above plot holes, Robert Zemeckis and Bob Gale have basically admitted that they just fudged it for the sake of convenient storytelling.
      • But they also said that there is a possible explanation, as clearly implied by what Doc says upon seeing the photo of the tombstone change in Part III: that time travel into the future takes you to the likeliest future of the way things are going at the moment when you traveled.
    • Perhaps the timeline "knows" Marty will eventually leave the future and go back to live his life up to that point? Or perhaps this is another facet of the above explanations for why alterations in the timeline don't immediately cause pictures and people to fade sometimes, but do other times.
    • My explanation is that we're seeing an altered timeline already. In the original one, they went to 2015, found out that Marty and Jennifer's older selves weren't present, and returned with disappointment. Then they grow up to become the 2015 Marty and Jennifer we see in the movie, meaning that 1985 Marty and Jennifer are now going to meet them in the altered timeline.
    • The Ripple Effect. We know that it takes a week to catch up to 30 years, but Einstein only went a minute into the future. His disappearance had already caught up with him when he arrived. Marty and Jennifer went 30 years into the future, so they would have had roughly a week before their 47 year old selves faded from 2015.
    • Incidentally, Marty never does meet himself in 2015. Jennifer does, but Marty doesn't.
    • The reason the way things work differently for Einstein is that Einstein is the only "person" (okay, dog) who goes to the future, and DOESN'T go back. There's actually TWO ways a person can meet themselfs/exist twice at the same time; the first, as mentioned above, is to go back in time and meet your past self, OR go to the future meet your future self, then go back in time, ride the slow path to the future, and then meet your time traveling past self. Since Einstein never went back, he really didn't exist during that 1 minute. Also, after BTTF 3 ( Unless the games say otherwise, I haven't played them) Marty lives out his life, and 30 years later Time-traveling!Marty comes does the his stuff, and leaves. Then 2015!Marty doesn't get fired, makes sure that Time-Traveling!Marty did things right, then 2015!Marty has a long heart to heart discussion with Marty Jr. to makes sure nothing like what happens again. BUT! the 2015 marty that we see in the 2nd movie DOESN'T know what is going on ( contrary to the original poster's theory ) because the delayed ripple effect hasn't reached him yet.
    • Here's a totally different possibility then the ones described above. (Or maybe it's the same as one of them, because Timey Wimey stuff is so hard to follow.) The 2015 that we see Jennifer and Marty visit in Part 2 is one in which they hadn't done any time-traveling since 1985; the middle-aged Marty we see had only ever visited 1955 and returned to the modified 1985, while middle-aged Jennifer has never been in the De Lorean at all. The reason this works is that Doc is the one who drives the folks to 2015 and so his perspective is the one that "matters". Here's how it looks from his view: After surviving the bullets with the vest in 1985, Doc decides to go visit the future. He does disappear for thirty years, and time goes on "normally" until 2015. Very shortly after the Doc had left, Marty has the car accident that we see him avoid at the end of Part 3. Sometime after that, it becomes apparent that Doc isn't going to come back, and this further contributes to Marty's psychological issues. In 2015, Marty Jr takes part in the heist and gets arrested. Shortly after that, Doc finally shows up from 1985. He sees the newspaper, grabs it and decides to prevent it. So he goes back to 1985 and picks up Marty and Jennifer, which would have caused an alternate 2015 except the Delayed Ripple Effect doesn't "catch up" then, and only after their arrival in 2015 do any "real" changes happen. As a general principle of BTTF metaphysics, you go to exactly the same future you came from unless your actions are such that there's no way that future could have occured (plus the Delayed Ripple Effect has some kind of complicated weeks-to-years relationship). So old-Biff returns to his original timeline and not the rich-Biff timeline because he left 1955 before the crucial juncture at which either young Biff started getting rich or Marty took back the almanac. I admit that it still doesn't make complete sense to me, though.

  • If Marty prevented Doc from getting shot, that means he never looked at his tombstone, which means he never traveled back in time to save him, which means Doc got shot, which means he did look at his tombstone, which means he traveled back in time to save him, which means...
    • Ripple-Effect-Proof Memory.
    • Doc had plenty of time afterwards to buy a tombstone and put the necessary information to get Marty to come back. The tombstone disappeared at first because it looked like Doc was going to survive and go back to 1985 that day. Ripple-Effect-Proof Memory prevented anything from happening then. When Doc stayed behind for Clara, he would have been able to plant a fake so it would be present in 1955. It's not like Marty and 1955 Doc dug up a body to confirm it.

  • If Marty prevented his son from getting arrested, that means he never got arrested, which means he never traveled forwards in time, which means he got arrested, which means he traveled forwards in time, which means...
    • Most of the stuff in Parts II and III inevitably leads to paradoxes in a "strict" mutable timeline, where subsequent timelines don't have "memory" of what happened "the first time around". One theory that's generally accepted on bttf.com is that in the BTTF-verse, any time traveler's memories from the first time around are transplanted to any subsequent iterations. It doesn't make any reasonable sense, but this assumption helps explain almost everything.
    • We call this Ripple-Effect-Proof Memory.
      • Actually, this isn't a case of Ripple-Effect-Proof Memory. Rather, it's a case of tangent timelines resulting in Doc's previous time travel and observing Marty's son's arrest not being affected, as it occurred prior to the time travel that prevents it. This could be argued to also be why we don't see a second 1985 Doc in 2015 - that Doc didn't travel to the same timeline, just as the 2015 that Marty travelled to doesn't actually get altered by Marty's later personal growth.
      • But if we're creating alternate timelines here, then Marty would never have been in danger of canceling out his own existence in the first movie. He would merely be in danger of returning to a future where he was never born and being effectively legally unpersoned. Alternate timelines prevent paradoxes.

  • At the end of Part III, Doc and Marty steal a locomotive. Their getaway plan is to go to 1985, which Marty does... but Doc doesn't, because Clara shows up. So why isn't he arrested for hijacking and destroying a locomotive? Surely the engineer would be able to identify him.
    • It was 1885. They were masked. The engineer had never seen the Doc before, and it's not like Doc Brown was a famous man before the hijacking; just a blacksmith. The strange men who took the locomotive didn't even want the carriages or anything of value. They didn't hurt anybody except themselves. And then they went over into the ravine, popular opinion being that they battled the heroic Clint Eastwood. All Doc Brown really needed to do to not be caught was not commit any more crimes and avoid meeting that engineer for a while.

  • The DeLorean's flying circuits are destroyed when it's struck by lightning. So does every thunderstorm in 2015 send cars falling from the sky?
    • Also the Delorean had a solid stainless steel body. For that precise reason it should have been protected from lightning strike. Aircraft are struck by lightning fairly regularly with no real damage due to the electricity flowing around the body and out the other side. This is also why it is safe to be in a car on the ground in an electrical storm, it has nothing to do with the rubber tires as has been so often misreported. Even the slight EMP produced by lightning should be shielded. See Faraday Cage on the other wiki.
    • Presumably, cars that were actually designed to fly have protection against this. The DeLorean was modified to fly, which probably bypassed a number of safety precautions in modern cars. Think of airbags and anti-lock brake systems on cars these days, which are designed to crumple instead of plow through obstacles. It's similar.
      • Except there's a commercial for ground-car conversions in the 2015 segment, suggesting that many cars we see flying around are modified terrestrial vehicles, not originally built to fly.
    • Actually, Doc states that in the future they have a very precise weather altering system. Presumably nobody falls out the sky simply because scientists found a way to make lightning never occur again.
      • It's not a weather altering system, it's a precise weather prediction system. Doc isn't making the rain stop at the beginning of Part II - he's checking the forecast to see the exact moment the rain will naturally stop.
      • Did we ever see anyone flying a car in 2015 during a thunderstorm? Possibly people just keep their wheels down on the pavement when the weather's bad, same as most IRL people avoid driving during a blizzard.
      • We did see cars in 2015 flying during a thunderstorm at the very beginning of Part II. The Delorean jumps from 1985 to 2015, ending up on the wrong side of the skyway.
    • Drivers could be willing to live with the (small) chance of encountering lightning. Slick roads and the risk of a crash don't stop people from driving ground cars during thunderstorms, after all. Plus, we know Doc survived his midair arrival in 1885, so perhaps flying cars have an emergency backup levitation system that brings them down safely if the flying circuits shut down.
    • It's possible that it wasn't just the lightning that destroyed the circuits — it could have been a combination of being struck by lightning, being propelled to speeds of 88mph+, accidentally travelling through time as a result and what was probably a rather bumpy landing in 1885 before Doc managed to get back in control of things, all of which presumably most 2015 air-motorists wouldn't have to worry about — but Doc was just over-simplifying to get the point across that the flight circuits were now useless. Alternatively, lightning can still fry most modern electronic devices to the point where they're useless if there's not a good surge protector on the lines, so it could have been something to do with that.

  • As soon as Biff in 1955 gets the Almanac and starts betting on the games, shouldn't that start to change the outcomes of the future sporting events, thereby rendering the Almanac useless eventually? At least once he became a famous, wildly successful gamester, the makeup and playing ability of given sports teams probably would have changed unpredictably.
    • Even if the almanac only works for the first few games, Biff can still get rich off of it. He becomes a millionaire on his first day of betting. Over the next couple months, he uses that million in more bets and makes more money. Let's say that at this point, For Want of a Nail, the book starts making mistakes. But what does it matter? Biff's already a multi-millionaire now. He can put his money into investments or whatever, so he keeps getting richer.
    • The results in the book would just keep updating themselves, the same way the newspapers change after certain events.
    • He became a millionairre on his first bet. Even a handful of bets would make him fabulously wealthy - the rules of all the sports events don't change all that fast, all at the same time. And as said, if papers from the future change, so may the Almanac.

  • Okay, in 1985-A, Doc was sent to an insane asylum. This means that the DeLorean time machine would never have been invented and that Marty would never have gone back to 1955. Therefore, when the Part II Marty goes back to 1955, the Part I Marty shouldn't exist there anymore. At least not until the almanac is burned, at which point the Part I Marty would be restored to 1955 via the ripple effect.
    • This is simple inconsistency. Without time machine invented through all 30 years (ALL 30, this timeline must not differ from others) and Great Night (what LP Marty had seen at the end of part 1) Marty-2 and Doc-2 must be erased and fade out. However, they have a whole week, while the events of Hell Valley happen just one night. P. S. This page need to be named The Movies for Noodlebakers.
    • Actually, since the time machine was never invented, it would undo all the previous trips through time, including the current one, creating a very convoluted paradox. The only way to get around this is to suppose that somehow, the time machine was still invented in the A timeline, and Marty still went to 1955 and back to 1985 and then to 2015. Actually, he's the Marty we're supposed to be following in 1985-A, since Word of God says (and it's consistent with other portrayals of time travel) says that he departed from 2015-A. We are, after all, dealing with Ripple-Effect-Proof Memory.
      • And a Ripple Effect Proof time machine. Once it (and its passengers) enter a time period, they become part of it (until they fade out, of course).
      • It appears from the films that the ripple effect doesn't occur unless the events that lead to what would be affected irrevocably changed, Doc and Marty had a working Time Machine so the ripple effect would not affect them in 1985-A, because they CAN change the events that lead to that timeline. This is also why Marty began disappearing at the dance, why Old Biff faded away when the Time Machine left, and why all but two photographs change instantly. Notably, the two exceptions have an affected event that wasn't going to happen until a week later. It's not so much metatime as the law of probability.
      • I didn't get a real good look at that newspaper (can you even * see* the date on it?) but I don't know of it saying that the committal happened in 1985.
    • I'm assuming he was committed at some point after creating time travel (which, since Marty already met him in 1955 and him aware, he may have gotten a head start on in Part I's alternate 1955-85). Keep in mind that if Biff had the Doc committed before the time machine was made, Alt85 wouldn't exist, because Biff would have no way to influence himself in '55.
      • However, even if Doc Brown was committed after inventing the flux capacitor, Marty has been shipped off to Switzerland for boarding school, so he wouldn't have traveled to 2015 to allow Biff to steal the De Lorean anyway. Damn these movies...
      • Only in 1985-A would the time machine probably not be invented. Not in 1985-original. Better that way: having two time machines from different timelines about would just open up too many new and mind-screwy cans of worms...

  • By 1900 or so, judging by Clara's dress and the age of his sons, Doc Brown has a steam locomotive that can fly, probably runs on phlebotinum and some sort of super-efficient steam engine in order to actually lift all that weight, and can travel through time. Even without bringing the time travel aspect into it, this is a hell of a departure from the technological state in our own turn-of-the-19th-century era. For comparisons, the Wright Brothers made their first flight in 1904 and air travel as a whole didn't really get started until WWI. This is such a drastic technological shift that by the time Doc goes forward to 1985, it should not be the same 1985 as Marty's. Doc couldn't built the new time machine in secret— he could have been able to get away with building or procuring a steam locomotive (it takes more than 1 person just to operate a conventional one!) and all the scaled-up-in-size parts and fuels to build the time machine part of it without someone to help him. Something about the project would have leaked out. If a sports almanac can change 2015 so drastically, antigravity should render Doc's 1985 completely unrecognizable from Marty's.
    • The Wild West don't have those meddling reporters, and during the Victorian years there was still many superstitions. It wouldn't too far-fetched that the Time Train could be even the same original train that pushed the Delorean, salvaged to the extreme (Any given train would need to be almost completly reconstructed, so working with some unclaimed remains would be still plausible) With some rebuilds, the controls mostly automaticed and Doc's Chemical Log you don't need many people to operate it, and hidding the big thing in a Doc-Cave, he could still be "That odd old Smith-inventor", and his greatest secret would be Clara's secret pie recipe.
      • I'm not talking about whether or not Doc has the technical knowhow to work on a steam locomotive—he built the time machine to begin with, and there are some hints that he likes trains sprinkled through the series. What I'm talking about is the simple fact that since a steam locomotive is much bigger than a car. Because of the size different alone—not to mention the challenges of finding all the materials for the Time Train and its modifications—Doc would have had to had some help building the time train. One man can lift a car wheel and many of its other parts himself, for example, but there's no way in hell he could manage a 5 foot or bigger wheel made of solid metal. Therefore, by implication, there are other people who know about the project, and the timeline Doc and his family end up in should be very different.
      • Don't forget that the derelict train would be a memento of Marty. Extra motivation to work, indeed!
    • Perhaps Doc Brown only overhauled the train to have time-travel capabilities in 1885. Since the time circuits were pretty big, he might've needed others to help put them together, sure, but nobody in 1885 is going to have any idea what time circuits are yet. Once the time stuff is set up, he and Clara (and their kids) actually jump to 2015 secretly, or at least more secretly than in the actual development, so no one in 1885 ever finds out what they were building; upon arrival there, they get the standard hover-conversion applied to the train.
      • Yeah, it seems pretty obvious how Doc did the whole thing without distrupting the timeline: 1) He somehow manages to repair the flux capacitator of the other DeLorean, the one which he hid in the cave. 2) He buys or steals a train that's similar to the one that sent Marty back to 1985, one that can accelerate fast enough for the flux capacitator to work. 3) He uses the train to take him and Clara to 2015. 4) Using 2015 technology, he builds a new flux capacitator that replaces the old in the train, and also gets it equipped with hover engines and whatever else technology the train he has. 5) He travels back to 1885, takes away the parts from the old flux capacitator that made it work again, and puts it in the DeLorean that's in the cave, so that Marty can find it in 1955, and the Doc Brown of 1955 can fix it. 6) He and Clara have adventures, have two kids. 7) They come to visit Marty in 1985. So it's possible to do the whole thing without anyone besides Clara knowing about the time travel technology, and without changing the timeline (Marty still has to find the DeLorean with the broken flux capacitator in 1955.)

  • The Grandfather Paradox no-one wants to talk about. In the first movie, Marty stops his parents getting together. This will lead to him disappearing, as he never existed in the new timeline in the first place. But, if he disappears, presumably he never existed to stop his parents getting together in the first place. So, logically this changes the timeline again, seeing as the new timeline cannot logically occur (no Marty to cause the change in the first place). Does this mean the timeline would eventually reset itself back to the original? If so, why is there any need for a story?
    • Or it might wipe out the timeline entirely when it can't reconcile itself. I believe Doc mentions this as a possibility.
    • It could be that this is the reason why Marty has time to fix the issue. The immediate expedient of causing him to cease to exist would trigger a paradox to destroy the universe. But time is just a facet of the universe. Marty can't destroy something so massive so quickly. So if there's a way for the causality to work out so that the universe continues existing (i.e. Marty getting his parents to hook up)the universe can hold together long enough for that possibility to play out.

  • "Clint Eastwood" was killed defending a locomotive. Couldn't this have caused massive repercussions for the career of the actor? Granted, it is conceivable that perhaps the real Clint's parents heard of this local hero, who had died 45 years earlier, and decided to name a child after him. However, isn't it possible that the young man, after so often hearing wild, inevitably exaggerated stories about this man, would chafe at the responsibility of living up to the name, and thus change it before heading to Hollywood? Alternately, he might have stayed far away from the Western genre so as to not invite comparisons? Either way, Marty was unknowingly risking massive consequences for the space-time continuum by using that alias.
    • You are grossly exaggerating the effect using that name would have. At most, it's probably just seen as an amusing coincidence.
    • And this is assuming that the literally unrelated Eastwood family is even aware of the origins of the name of a local geographical landmark near a fairly small out-of-the-way town that date back twenty years before his father was even born and see it as anything more than a mild curiosity; 'Clint Eastwood' didn't exactly become a national legend, after all. FWIW, though, Clint Eastwood was named for his father (his full name is Clinton Eastwood Jr.), so his father was presumably the one named for the hero figure to begin with if even they were aware of it.

    Fading 
  • Speaking of fading, why could the characters notice the fading? Marty might have been able to remember his brother and sister having been in the photo, but what sense does them gradually fading bit by bit have? They could have had more realistic changes, that could have actually happened without the effect of time travel, had things simply gone differently. Marty could have still felt ill as he had, simply without fading, maybe it get worse and all of a sudden it stops and he's now got a Lone Pine ID card or something in his wallet next to the photo (which would then contain his siblings again). The individual siblings disappearing could be handwaved as the time stream trying to keep George and Lorraine together, it just takes longer and loger and they have fewer kids every time something doesn't change, but really, why would Marty have been born the same age, with one hand, and the ability to play the guitar, had his parents not kissed at the right point in time? (summed up well in this comic). I've asked before, but the last time I mentioned it I got yelled of the forum for it not being relevant, mere days before the comic was put on the web. Please take it seriously.
    • This one has to be chalked up to rule of Plot Purposes. If Marty faded out, or things changed overly dramatically (he suddenly didn't have siblings) then he would have failed in his mission to leave history unchanged. In essence, he would have killed his brother and sister. There's absolutely no reason for time travel to work the way it does in the movie unless you consider that changes are a wave that slowly travel forward in time from the point of change (in other words, a change in 1955 takes three days to fully register in 1985), and that doesn't make any sense. But since we're dealing with hypothetical situations that can never really occur, it pretty much happens because Word Of God says it happens that way. It's a cop-out explanation, but a scientific or realistic answer is impossible.
    • I took the picture as being "readjusted" to fit with the new timeline, where his brother (his sister, and later himself) wasn't born, but had to work through the Time Travelers Immunity that the photo possessed so this process took a while.
    • My pet theory is that the picture is a quantum superposition of all possible pictures, so that the net effect is that the viewer sees the most probable outcome. So Lorraine and George might still get together without Marty's help, but perhaps not in time for Dave to be born. As events progress, it becomes increasingly less likely that Lorraine and George will hook up at all, so the picture gradually fades to blankness. When Lorraine and George kiss, the probability of Dave, Linda, and Marty all being born on time snaps back to 100%. (This also explains how and why the YOU'RE FIRED fax faded away, but it does imply that "facts" as recorded in Gray's Sports Almanac keep fading in and out.)
      • There's evidence supporting this in Part III: when "Mad Dog" Tannen arrives at the saloon and calls out Marty for their showdown, Marty hesitates and looks at the photograph of the tombstone. The tombstone was previously blank, but the name "Clint Eastwood" (Marty's alias) begins to fade into view, indicating that he will die if he goes out.
      • The picture is between depictions of alternate situations because reality itself is that way. That may raise more questions than it answers, but there you have it. The situation of whether Marty and his siblings will ever be born wasn't nixed entirely when he prevented George from being hit by the car, as the climactic events of the movie in question prove. Therefore the closer the situation got to the point where Marty and his siblings would never be born, the closer they got to fading from the picture, and for some reason (probably either the same one or just for dramatic purposes, Rule of Cool) Marty himself started to fade as well. When it became certain again that the three kids would be born, Marty and his siblings were firmly reestablished once more. Still, one wonders why that photo would have been taken without them in it.
      • Presumably in that instance the photo would itself fade away shortly after Marty did, there being no reason for it to have been taken (or it would have been replaced by whatever photo had actually been taken on that particular filmstrip in the new timeline). Similarly with Marty's clothes, which I believe were also fading (and if they weren't, they probably would shortly after Marty).
      • That's also easily explained with the Ripple Effect explanation: Marty was born in 1968, but the picture was taken much later, for sake of simplicity I'll say 1985. Which means that first Marty&siblings fade because the years they'd be born come and, well, they aren't born, thus ceasing to exist. That also explains why Marty is the last one to fade. THEN comes 1985, and the exact date the picture was taken and the picture is either never taken or is of something else entirely, so it'll take longer for the picture to accommodate the changes to itself as opposed to the changes in the subjects it shows.

  • I've got a puzzler. Why does Marty start fading when he does? Remember, this is after George fought Biff, took Lorraine inside, started dancing and got pushed away by a bully. Thats when Marty starts fading, which implies that George is about to give up and be a milquetoast. But with no intervention from Marty or Doc (who is too busy preparing for the lightning) George steels up the nerve to attack the bully and kiss Lorraine, then Marty is fine. So the timeline was always going to be George having to stand up for himself one more time. Marty shouldn't have faded at that moment. Unless hearing a guitarist suddenly fumble over his chords (the only change in Marty's behavior) was all George needed to nudge him into standing up for himself again. And if thats the case, you'd think his hard rock version of Johnny B Goode would have cause additional siblings. ;)

  • In Part II, Old Biff collapses after emerging from the time machine, having what appears to be a heart attack. One interpretation is that time-travel was too much for his heart. But an alternate version shows him fading out. One of the Bobs said that this was because Lorraine shot and killed him in the 1990s. So of course, Biff never existed to take the sports almanac back to his younger self. So at what point would the reality shift ripple restore the timeline where young Biff never gets the almanac, if Marty and Doc failed to set things right?

    Relationships 
  • I never noticed this until another website (cracked.com?) made a point of it. At the end of the first movie, George is an assertive, fulfilled guy, and Biff's a submissive blowhard, no longer any kind of threat. All well and good, but even under those circumstances I'd be a bit leery about the guy who tried to rape my wife back in high school having unfettered access to my home and car, no matter how defeated he may be.
    • It's never told what all happens in the 30 years after The Punch, but that is a great deal of time for even someone like Biff to completely reform and prove it to the McFlys, as he clearly has done at the end. Maybe some people are never willing to forgive even after all that time, but George and Lorraine are likely good-hearted people who truly see the change in Biff. It's actually a nice Aesop.
    • As well as the above, in the new timeline, New Assertive George McFly has already kicked Biff Tannen's ass once before, and by the end of the movie doesn't seem to be willing to take any crap from the other high school bullies who used to push him around. 30 years is plenty of time for George to make it pretty clear to Biff that if he tries anything of that nature again, he's going down hard.
    • Factor in some values dissonance, probably. Back then, rape... or even attempted rape... didn't occupy the place in public conscience it does now. Lorraine and George may have been raised so that they considered Biff's actions just a sign of immaturity... not a good thing, but a "young people just do stupid stuff" sort of thing. By the time rape, even attempted rape, became acknowledged as the unforgivable act it's considered today, they probably would have already gotten over it, forgiven him, and so on. What would they do, decide to get themselves all riled up and hate him again just because society was now open about the fact they were supposed to?
      • Also see UsefulNotes/TheFifties. Even if Biff had raped her, society might not have considered it Biff's fault.

  • At the end of the first movie, Marty tells Lorraine his real name. Lorraine clearly likes the name, implying she will eventually call her child that. The only thing... Marty was not her firstborn son. So why didn't Dave end up being called Marty and Marty end up being called something else?
    • Maybe she liked the name Dave even more.
    • Dave was her previous fling (she sure seemed to have no trouble throwing herself at a stranger, which implies she wasn't exactly unfamiliar with that kind of situation)
      • She certainly had at least one boyfriend prior to Marty, given that she said "it's not like I've never parked before."
    • Maybe the father chose the name of the firstborn son. Then Lorraine chose it for the second son.
      • Additionally, the pop-up trivia information on one of the DVD's of Part III says that Marty's having an ancestor by his own name is an indication that he was likely named Martin partially after that guy as well.

  • How come Marty doesn't have any ancestors who look like George, Dave or Linda?
    • He probably did, but we just didn't happen to meet them over the movies.
    • How come Shamus, Marty Jr., Marty's daughter and William Mc Fly (as seen in the old photograph in the library) all look like Marty, yet George looks nothing like any of them?
      • Real Life answer? Crispin Glover wanted more money than the studios would pony up, or so I hear...
      • The Telltale game has Artie McFly, Marty's grandfather/George's father, look and sound roughly like Crispin Glover.

  • George never found it just a bit strange that Marty grew up to look perfectly identical to Lorraine's old fling?
    • Unless George has photographic memory, he's probably not going to remember very well what a guy he knew for a week thirty years ago looked like.
      • Or maybe George noticed Marty fading away and figured out what was happening. It's farfetched, I admit, but it would shed light what was in George's book that everyone was so excited about.

  • In the original timeline, there would have been an obstacle to George and Lorraine's relationship: Biff's bullying George. Since Biff wants to make Lorraine his girl, it would be out of character for him to react to the George/Lorraine relationship in any other way than by ordering George to stop dating her. And since Original Timeline!George was incapable of standing up to Biff, he would have caved in and they never would have gotten married. I suppose, though, that if Biff moved away from Hill Valley after high school, then George could have dated and married Lorraine without being disturbed, and once they were married, it would be too late for even that level of bullying to break them up.
    • Maybe Lorraine did all the standing up to Biff. Either way, I think it should be noted that Biff wanting to marry Lorraine is a Retcon made by Part II. In the first film, he didn't seem to have any particular interest in her other than wanting to get in her pants.
      • Maybe that's what Biff meant, and we only see Biff marry Lorraine in 1985A merely because he was envious of George?
      • Also, I'm sure that Biff did harass other girls - besides Lorraine. I think part of why he marries Lorraine, in 1985A, is because of how she ended up marrying his former target. Remember that he had resentment issues towards George, too.
    • Simple: Original!Lorainne falls for Original!George. Biff no longer wants her, coz he's a cool guy and why go for a girl with such poor tastes in men? It reflects badly on him. LP!Lorraine dates LP!George, who is now cooler, running for class president, and later a successful author. She is thus still attractive to Biff coz she has pizzaz. It's worth it then to murder George and take his wife, she's no blemish on Biff's reputation.

  • The potential answers to many of the above are on the DVD box set documentaries. In it, the writers mention how their original idea is that there was some time-governing entity that had limited power in regulating events. It had a general outline (i.e. George and Lorraine get married and have their three children) and otherwise manipulated events to maintain this.
    • In Spite of a Nail covers it quite well. In the BTTF universe, unless something happens to prevent an event from occurring as it did in the unaltered line, it happens. Slightly modified in detail, perhaps, but close enough for jazz rock and roll.
      • That concept seems to be contradicted by other things in the series that show large future changes from relatively trivial changes to the past. For example, Marty's family at the end of the first movie seem to have radically different personalities, jobs, etc., apparently all because Marty's dad punched a bully in 1955. It seems likely that they could have found ways to be losers if that was really what they were "fated" for and some entity was pushing them in that direction.
      • Actually, this is answered by basic rules of the universe. Matter can neither be created nor destroyed, but pretty much anything else goes. If, barring extreme alteration, George and Lorraine were meant to have three children, then the actual personality, nature, and ultimate outcome of those three children is immaterial. Look at it this way... suppose you have an area with a cube that has thirty grams of matter in it. The universe doesn't care if this matter is cube-shaped, spherical, painted red, painted green, rendered into a dense cloud of particles, or is a very cute squeaky mouse, so long as there is thirty grams of matter there. Barring some serious fuxing of the laws of existence, all it cares about is the amount of matter, not the state.
      • That won't work; by the same token, the universe doesn't care whether the matter comes together in the form of three children or not. The matter that makes up the children came from the food that Lorraine ate during her pregnancies, and that the children ate after birth. If the children had never been born, that matter wouldn't be destroyed; it would have been eaten by someone else, or rotted.
      • Going by the summary above, according to the writers, someone or something in-universe does care. Which puts this into the realm of Deus Ex Machina and/or A Wizard Did It.
      • Chronal inertia. The "small change" of George belting Biff had 30 years to snowball into the different personalities (and decor, and jobs, and cars).

  • In the altered timeline created by Old Biff going back in time in Part II, why did Lorraine marry Biff?
    • I figure that it was due to George Mc Fly being murdered and Lorraine being stuck with three kids who she had trouble supporting. Lorraine probably married Biff so that both she and her kids could be secure (and she probably wasn't aware that it was Biff who killed her husband). Notice in Part II when Lorraine threatens to leave that Biff threatens to cut off her kids, at which point she backs down.

     Technical Details 
  • If Plutonium/Mr. Fusion is only used to power the actual time travel components of the DeLorean, why did it keep shorting out during the first movie?
    • Truth in Television. One of the main reasons why DeLoreans were unsuccessful as cars was that they had incredibly unreliable ignition.
    • For that matter, why is plutonium/Mr. Fusion relegated to powering time travel in the third movie, when Doc specifically says in the first that the car itself is electric?
    • No, he says that the time travel circuits are electric, but need such a huge electric charge that plutonium is the only way to generate it. The car itself is clearly gas-powered.
      • To be specific, Marty says "You're saying this sucker is nuclear?!" and Doc answers "No, no, this sucker's electrical!" It could easily have been interpreted that Doc made the entire car run on electricity, since gasoline doesn't become an issue until the third movie, which is the first time Doc says it works like a normal car otherwise. It's entirely possible that originally the car was intended to run off of Plutonium/Mr. Fusion, but when they needed a plot device for the third movie, decided it actually needed gas.
      • ^ If the Part 1 Delorean was intended to be electric, why does its engine sound like that? Electric engines really don't sound like gas engines.
  • At one point, Doc sets the time circuits to the year "0000", which doesn't exist (Jesus was born in 1 AD, and the year before that was 1 BC). What would happen if the DeLorean had tried to travel to that time?
    • Presumably, it would extrapolate the year from its dating system and thus arrive in 1 BC.
    • Historically, the year of Jesus' birth isn't known, but was most likely around 3-5 BC. The modern Gregorian calendar isn't too precise that far back.
      • This troper remembers hearing on the commentary that that was a joke.
      • Wikipedia tells me that "astronomical year numbering" has a year 0 (what we would call 1 BC), and then it counts -1, -2 etc.. Maybe the Delorean is set to astronomical time. Or whatever.
      • Doc wasn't actually going there, he was illustrating an example...slightly dumbed down for the audience, of course. This is particularly the case given Jesus wasn't born on December 25, which is the date Doc typed in.
    • As I mention on the WMG page, I would estimate that if you had to travel to B.C.E. years, the four-digit display would just change color. And there technically was a year zero, it just wasn't called that.
      • Also, as the DeLorean only travels through time and not space, even if the Doc was able to travel back to December 25, 0000 to witness the birth of Jesus Christ, he would have arrived in the land which would one day become California, and would have had no means to travel to that stable in Bethlehem in time to witness the birth in the first place! For this troper, this headscratcher overrides all ideas of the year 0000 not existing.
      • He'd have had a means of travel —- the Delorean can fly. But he wouldn't do it, because I can't think of anything that would do more damage to the timeline. That said, I now have the urge to write a Fan Fic where the star that the three wise men followed turns out to be the Delorean.
      • The DeLorean was not hover-converted until the end of Part 1. Doc was probably just goofing off anyway.
      • He was just giving Marty some examples you could travel to with a time machine, like the Declaration of Independence or the birth of Christ. Doc doesn't seem to be kind of guy to know much about religious history, and just thought "Christ was born on Christmas Day, at the beginning of the calendar dating", thus December 25, 0000. As for the wrong location, I just can't picture him saying: "Or witness the birth of Christ?" *sets digits to DEC 25 0000* "Of course, you'd have to travel all the way to Bethlehem first, because the De Lorean can only travel in time, not in space, you know." He was just giving some quick examples.
      • In the novelisation, he says almost precisely that.
      • (Or you could just say Doc's not much of a historian.)
    • He's probably just giving a dumbed-down explanation for Marty. Doc might indeed be perfectly aware that the Birth of Christ didn't actually occur on December 25th in the year 0, but he's also probably aware that Marty — hardly the most Book Smart of people — most likely isn't going to be. Since Doc's just rattling off a few well-known historical dates simply to illustrate a point, he decides to go with one that Marty is likely to recognize regardless of accuracy simply to underscore the fact that the Delorean can, theoretically, go any time.
  • The time circuits are clearly limited to four-digit years. So what would happen if you went to 11:59 p.m. on December 31, 9999 and waited one minute?
    • The Y10K bug strands you in a post-apocalyptic wasteland...obviously.
      • Maybe 9999.12.31.23.59 would actually result in a BC year if the computer is running with signed integers.
      • In one Fan Fic I read once, Emmett mentioned that the vehicle COULD go back further than a year with four digits; he just figured that not many people would want to do it.
      • If the time circuits measure time in minutes after 0000-01-01 00:00 (assuming a proleptic Gregorian calendar with no 4000-year rule), then the smallest amount of memory that could be used to express all values from then until 9999-12-31 23:59 would be 33 bits (unsigned). This would actually cover it until approximately the beginning of April 16332, but you might have trouble seeing it on the Present Time display. If they measured time in seconds following 0000-01-01 00:00, you'd need at least a 39-bit unsigned integer, which would cover you until roughly mid-January 17421.
      • I don't think Doc ever planned to travel that far in time. The machine may have been intentionally built not to be capable of it, or he may have had some technical solution, or been able to think one up, if he changed his mind.
      • If he didn't stop at four-digits, how many was he going to stop at? Five? Six? 34? 24187? It probably would have been a bit mind-boggling even for the Doc to travel to build the Delorean with the ability to travel to infinity and beyond.
      • Besides, a 4-digit year is a good cut-off point as that can theoretically get a person back as far as the Late Stone Age.
    • I don't think he'd ever deliberately go that far into the future. Traveling 30 years into the future is risky enough. Who would have the slightest idea what to expect in the 100th century? The Earth might have been rendered completely uninhabitable due to nuclear war or something.
    • Just because the machine has no way to display an information, doesn't mean it can't process it; or do your computer cease to work when you turn your monitor off? Or does the mcdonalds logo actually cease to be red an yellow (as in, its data) may the red color of your monitor bug out?
    • If you need to go to a 5-digit year, the display probably just switches to a scrolling format. (Assuming, of course, that the De Lorean can even travel that far.)

  • The DeLorean obviously travels through time, but how does it also travel through space? Consider this: the Earth is tearing through space at fantastic speeds. Even when Doc sent Einstein on a just one-minute trip, the Earth still will have moved quite a bit. If Einstein's coordinates only move through time, and not space, shouldn't he pop out in outer space, where the Earth was one minute ago?
    • See Time and Relative Dimensions in Space.
    • Perhaps the Flux Capacitor locks itself onto a gravity well
    • There are no absolute coordinates in the universe anyway. If it stayed in place, it would have to be in relationship to some other object. Might as well make that object the earth.

  • So, does the DeLorean need to be going at 88 MPH or does it just need to achieve that speed? Put another way, if you were going at 89 MPH and you turned on the time circuits, would you go back in time or would have to drop down to 88?
    • My guess is that you have to accelerate to 88 miles per hour with the time circuits already on. But what about flying? Is 88 miles per hour the ground or air speed? What about flying against (or with) the wind?
      • Probably it's relative to the speed (and direction? maybe?) at which you turn on the time circuits, so that's why they mostly start from a dead stop to simplify gauging the speed.
      • More than once the car time travels from the air onscreen.
    • Obviously the DeLorean has to be moving forward at 88 mph, not just spinning its wheels. If all Doc had to do was get the wheels spinning at 88 mph he could just jack the back of the car off the ground and gun the engine until the time circuits kicked in. Which would've been much safer, since there'd be no chance of crashing into a tree or a building or something that doesn't exist in the time you're coming from but does exist in the time you're going to. Somehow I don't think even Doc Brown is reckless enough to take that risk if he knew he didn't have to.
  • Also, why has it to be 88 MPH anyway? Is it just an arbitrary setting by the Doc? If so, he probably could have changed it when they were stranded in 1885 to a lower speed, perhaps the speed they could reach and maintain using the horses... So this can't be it...
    • Probably has something to do with how the Flux Capacitor works. Chalk it up to some weird law of science, like the speeds of light and sound.
    • To quote Doc: "The way I see it, if you're gonna build a time machine into a car, why not do it with some style?" If someone like Doc is to create time machine, why not to put some obstacles to remind the time traveler that this deal is not just playing in the sandbox? You need to think many times to dare to interact with time. While you accelerate, you can think again.
    • I figured that Doc programmed the time circuits that way. He could have had the Flux Capacitor calibrated to activate at any speed. When the lightning strike fried the time circuit control chip and sent him to 1885, the technology to reprogram it didn't exist.
    • Willing Suspension of Disbelief and Rule of Cool.
    • In the DVD commentary, the filmmakers state that they chose this particular number because it's easy to remember. If you're looking for an in-universe explanation, I got nothing.
      • It cannot be a gag because, contrary to popular belief, the Delorean's speedometer does not go up to 85. It goes to 95.
      • Not true. The original DMC-12 used a stock GM speedometer. In the early 80's (circa 1981 when Doc's DMC-12 was presumably built) US Federal law dictated that speedometers only go up to 85. Note that John De Lorean himself worked as a GM bigwig for years, and despite the Renault engine, many parts of the DMC-12 were taken from existing GM stock.
    • It's probably 88 MPH due to this number, when displayed on a two-digit digital readout like the one in the film, uses all 14 light-able segments.
    • Not to mention it makes for a far more gripping climax for the first and third films if Marty has to gun the engine up to eighty-eight. How boring would it have been if you only needed to get to three miles an hour? The third movie would have been over in a third of the time.
      • Perhaps Doc picked this number to avoid having accidental activation of the time machine. 88 is faster than highway and residential speeds, so if Doc is driving the De Lorean somewhere and accidentally turns on the Flux capacitor and time circuits (due to malfunction or something), he doesn't risk zipping off to the crucifixion in the middle of I-90.
    • Since "flux capacitor" is a mish-mash of electromagnetic terms, and Doc said that the DeLorean's steel frame is important, I'd guess it has to create a powerful electromagnetic field to trigger the time jump. A moving electric charge creates a magnetic field and vice versa, so Doc's apparently either charging or magnetizing the DeLorean's exterior, and then speeding the car up to generate a strong enough EM field. 88 mph just happens to be the magic number.
      • Hey, maybe it's generating EM by interacting with the Earth's magnetic field! And thus, the whole trip is coordinated with the earth. Thus, you always wind up in the same spot you left, relative to the Earth. Incidentally, this means that you couldn't use the DeLorean in space. Also the EM idea explains how the flying DeLorean at the end of Part 2 managed to go back in time, despite not moving at 88mph relative to the ground at that time. That DeLorean was struck by lightning (directly), which provided such a powerful EM field that it didn't need to be moving forward.
    • Doc calibrated the time circuits to 88 MPH because it's a speed one is unlikely to reach simply driving around to the store to get some milk. Thus by accelerating up to that speed means that you are deliberately attempting to travel though time and not setting the damn thing off accidentally. It seems that as long as a destination date is punched in as soon as you hit 88 mph the time circuits activate and away you go, and since there is ALWAYS a destination date displayed the car is always "active." It's a machine that he designed for the express purpose of moving through time. The reason why it's a car is because you want it to go places and the reason it's a DeLorean is because the stainless steel skin optimizes flux dispersal.
      • I think I've got it. It's a little joke by Doc Brown. To travel through time, you must (on Einsteinian theory) exceed lightspeed. Exceeding lightspeed in theory means your mass goes beyond infinity, yes? Which is unbelievable on its own, but you must then somehow catch up and reassemble the infinite number of photons that have spun out since the moment you want to go back to. That would be a task in the order of double infinity, yes? Turn the number "88" sideways and tell me what you see.
      • Four boobs?
    • I always assumed it was an issue of assisting the flux capacitor, under the assumption that time travel works by creating excessive amounts of energy (hence a lightning-bolt's worth of electricity run through a fancy capacitor), and that 88 mph was just an additional way of adding further energy to the De Lorean (in the form of kinetic energy). 1.21 Gigawatts + Capacitor + 88 mph of velocity together met that energy requirement.
      • I might be thinking on the same track as you with this. You see those crazy sparks that appear in front of the De Lorean as it accelerates? I'm thinking that those sparks have to be traveling somewhere between 87 and 88 miles per hour. When the De Lorean runs into those sparks, they've created sort of a portal through time, that's even what it looks like when we see Marty's first trip through time from the inside of the thing.
      • That may actually be the best of all of the explanations - the flux capacitor sends out energy in such a way that, in order to latch onto the same location on the earth's surface in both times, it must actually emit forwards along the earth from the capacitor itself at 88 miles per hour. The car must be travelling at the same speed in order to actually be within the resulting portal.
    • Possibly the time circuits are capable of generating a stable wormhole just long enough for a Delorean-sized object to pass through at 88 mph before it collapses.

  • What actually powers the flying ability of the Delorean? I know it became a moot point when Doc said that the flying circuits were fried by the Lightning Bolt, but if the Time Circuits & Flux Capacitor were powered by Mr Fusion & the Internal Combustion Engine was run on Gasoline, what was the Hover ability run on?
    • It's unknown, just whatever hover conversions needed (Goldie Wilson III can do that for you!)
    • Mr. Fusion powers the flight circuits and the time circuits.

    Other 
  • Perhaps this is a stupid question, but did bulletproof vests that could protect you from several 7.62 rounds fired at relatively close range, exist in the 80s? I've been investigating a bit, and from what I read the standard issue back then in the US military was the PASGT vest, which was only Level II (meaning it could stop most handgun rounds, but not rifle rounds), and even modern day armor will only save you from an AK if you are wearing ballistic inserts underneath the vest.
    • It's already been discussed above. I think general consensus is that Doc Mad Scienced the vest to beef it up.
  • We know from the newspaper clippings seen in the opening that Brown Mansion burned down and that Doc subsequently moved into his garage, selling the rest of the land to developers. However, the scene where Marty leaves the garage in 1985 shows that these developments have resulted in Doc having his residence in the middle of what is clearly a commercial district. Would any kind of zoning commission allow this?
    • Zoning changes over time. Since Doc Brown needed the money from the developers, he wouldn't have spoken out against changing the area around his home from residential to commercial. He probably would have supported it since it would have helped in the sale.
      • Yeah, but would the city allow him to continue living there?
      • If he made it a condition of the sale, and they wanted the land badly enough to put up with that condition being in the contract...
      • Could be that the building is technically identified as a commercial building (i.e. it's his workshop or something) but he keeps a bed and just happens to sleep there; kind of like all those movie private investigators who seem to basically live in their offices.
      • This also doesn't preclude that his part of the lot has always been zoned as residential, but the rest of the area was rezoned for commercial over the years.
  • What were a couple of Libyan terrorists doing in Hill Valley, which seems to be an at least somewhat obscure place, anyway? Did they deliberately seek out the Doc knowing that he could build them a bomb?
    • Doc probably previously contacted them as an attempt to get some Plutonium, chances are he told them if they could get him some we would use it to make a bomb. This obviously wasn't in Hill Valley at the time, as he hadn't expected them to track him back there.
    • Also, if I were a terrorist, I'd be a lot happier with a time machine than a bomb...
      • Also, if I were anyone, I'd be a lot happier with a time machine than a bomb...
      • It is perfectly clear that they didn't * know* about the time machine. That was part of Doc's ruse. And yes, Doc may have contacted them, or they may have heard of him and contacted * him* instead (he may have had impressive past accomplishments that the derisive natives of Hill Valley don't know about, don't care about, or disbelieve; Gale and Zemeckis said that they think of him as having probably worked on the Manhattan Project).
    • People who have suspicious and illegal transactions to make would probably prefer the more obscure, the better. As such, if you're arranging to acquire some stolen plutonium for a terrorist plot, then why not some quiet, obscure little town where no one's really going to be on the lookout for that kind of thing?
  • Biff Tannen. How does someone with obvious homicidal/sociopathic tendencies get to run around free as a bird without any kind of recourse? Young Biff was willing to run over another human being in full view of the public, as well as trying to run the same human being into a tunnel wall with his car a few nights later. He was also tried to rape another student. Older Biff was an unapologetic drunk driver. Why is he not in a sanitarium for the criminally insane?
    • It was The Fifties. Stuff like that happened a lot.
      • He didn't * succeed* at those crimes, so he couldn't be charged with them. Maybe with attempting them, but that wouldn't automatically land him in a sanitarium (he clearly isn't insane), and even if it did he might be out of it even more quickly than in prison. It's not like someone is likely to go to prison for life just for * attempted* murder or rape, and those who witnessed it might have been too afraid of him to come forth with it. The direct victims seem not to have pressed charges.
      • Considering that in the movie, half the time young Biff's intended victim was Marty, who couldn't press charges because (1) he wasn't supposed to exist (what would he do if the police or judge asked him for ID?), and (2) Doc wouldn't have allowed him to, as it would screw up the timeline (not to mention that, after the first manure-truck crash, if Marty had pressed charges, the trial would probably be scheduled after Marty would have to hit the lightning bolt at the clock tower to go back to the future).
      • And maybe he did spend the night in jail after crashing into the manure truck, and his grandmother had to come bail him out. It could explain why she always sounds so grumpy whenever she asks him where he's going ("BIFF! Where ya going this time?!?").
    • Isn't he implied to be a high school football star? Cops have certainly cut corners for guys like that in real life small towns, it wouldn't surprise me if it was the same there.
    • Because he's clearly not criminally insane; he's an entitled high school bully, not the Joker or anything.
  • Not really a JBM, but merely an observation: if my calculations are correct, there are no less than four DeLoreans in Hill Valley'on November 12, 1955:
    1. Marty's DeLorean he brought back from 1985 to 1955;
    2. The DeLorean stolen by Biff and brought back to 1955;
    3. The DeLorean stored away in the Delgado mine in 1885 and recovered in 1955; and
    4. The DeLorean Doc and Marty used to get to 1955 from 1985-A.
      • Not so fast. From the audience's (and black hat Marty's) POV, the Delgado DeLorean wouldn't be in the mine yet, because 1985 Doc hadn't been struck by lightning yet. Simple cause-and-effect. The very moment Doc was accidentally sent back to January 1, 1885, the ripple effect kicked in, and the DeLorean would have been in the mine. Thus, only three DeLoreans in 1955. (Except if Marty does some retrospective thinking later on. He's gonna be stuck trying to figure out that ripple effect for a LONG time to come.)
      • Also, as I wrote above, it can be argued that regular 1985 DeLorean and 1985-A DeLorean are one and the same after the Ripple Effect kicks in as both Twin Pines Marty and Lone Pine Marty traveled from the same point in space to the same point in space, but more than that, phasing into existence at the same time and at the same place, so either they both merged into a single one (also merging both Martyes) or one of them was destroyed from existence (safe to assume it'd be 1985-A as it got there "latter").
  • This one does bug me, though: in the first film, before he heads off to make his run back to the future (heh heh), Marty tells his parents that if they ever have kids and if one of them when he's eight years old accidentally sets fire to the living room rug, to go easy on him. The implication is that Marty's referring to himself. Only problem: if, as is implied, Marty does retain his memories of the TP timeline only, and doesn't gain the memories of the LP timeline, how can this make the slightest bit of difference to his own life? I realise it's more in there for a joke, but it doesn't make sense. More to the point, why the hell, having just barely avoided fading out from his own messing around with the timeline, having been warned repeatedly by Doc that he's not to interact unnecessarily with people from his own past, would he then consciously do something which could potentially start the damn problem all over again?
    • Marty wouldn't actually know at that point how the memory thing works. As for way he'd do something that would risk messing up the timeline... well, Rule of Funny, I guess.
    • This troper actually has a point. Lets say that at first either George, and/or Lorraine didn't want children at all, and that Dave was an accident, but they decided they loved being parents and had two more children. Marty bringing up their future kids could have brought up in the conversation that George or Lorraine or even both didn't want children, which could have led to an argument, causing them to break up, thus, no more Marty!
    • Like all fallible characters (and all fallible people) Marty does dumbass things sometimes, and this is, if anything, one of the more understandable instances of it. Remember that his total incomprehension of all the time travel logic Doc tells him about is a repeatedly made point. He's just a kid who doesn't really understand all this timey wimey bullshit, and he was acting in the moment on a natural impulse that anyone might have. Plus it made for a hell of a gag. Far less clever people than Marty have endangered themselves with greater obliviousness before, both in fiction and Real Life.
    • Even by the standards of Headscratchers / WMG, I think we're really over-thinking things a bit here. George and Lorraine have literally only kissed for the first time a few minutes before this conversation takes place and have been boyfriend / girlfriend for a grand total of, what? A couple of hours, tops? Which — even today, let alone the 1950s — is waaaaaaay too early in a relationship for most people to even think about the possibility of having kids with each other, let alone discussing, arguing about and breaking up over the subject. The only possible realistic reaction they would have had at that point to Marty's comment would have been a slightly bewildered "Huh, that was a weirdly specific thing to suggest" before they both completely forgot all about it. And since they would have presumably had a similar conversation about having kids at some point in the future without breaking up about it with-or-without Marty's presence, and it presumably ended more-or-less okay then, really, what's the harm in bringing it up? In other words: it's just a joke.
  • Something I discussed over (quite a few) pints really ended up bothering me. So on Doc's "personal timeline" he ends with a time machine (the locomotive) and pretty much full knowledge of the events of the movies. And he's shown himself to be sort of Doctor Who-ish in his ability to trust other "versions" of himself. Why not just use the train to go back and let himself know at various parts what he has to do to ensure the "ideal" future. He could have just traveled to 2009, printed off this page, delivered it to himself in 1985 and saved Universal millions making the the movies.
    • Why would he want to do that? Didn't everything pretty much work out perfectly in the end. Why would he want to risk messing that up?
      • Because he already did it at least once: he heeded Marty's letter warning him of his own death, and took steps to prevent it, way back in the first movie:
        Marty: What about all that talk — about screwing up future events, the space-time continuum?
        Doc: Well, I figured, what the hell.
      • But in that case he actually had something to prevent, namely his own death. As of the end of Part III, what would he want to prevent? George's success? Biff's comeuppance? Marty avoiding the auto accident? I don't think so. He wouldn't change anything because there's nothing to change. Everything is already perfect.
    • For this to work, the Doc would have to travel through time talking to other versions of himself. In II he makes it quite clear that he and Marty should not be interacting with their older selves, and goes to great lengths to avoid his older self seeing his face in the Square (although really he should have had the sense to avoid that area entirely). Also, doing all this could have created a paradox where he never ends up in 1885, and thus never gets the chance to create the train time machine.
      • To be fair, he probably couldn't avoid that area entirely if he wanted to get to where he was going without delay; the town square is usually named so for a reason, it's often the main central thoroughfare for the community — and certainly would have been so back in 1955, when the town was much smaller. Chances are, it would have either been impossible or impractically time-consuming to get from A to B without passing through the square, so he's got little choice but to risk it.
    • Well, maybe the films aren't an adventure as we all think but instead an adventured-out auto-biography of Steven Spielberg? Makes you think, doesn't it?

  • At the end of Part 3, how the heck does the railroad crossing gate know to come down when the only train that's coming is coming from god-knows-how-many-decades in the future?
    • Isn't that standard? Where I live, crossing gates come down quite a bit before the train shows up.
      • But that's presumably through a motion detector or something. The crossing gates in the film came down before the train arrived in 1985 when there was nothing to detect.
      • Sorry, got confused. Thought you meant the first train, that destroyed the Delorean.
      • Obviously, the sensors that lowered the gates because of the Delorean-destroying train aren't right at the crossing, but some distance away. This makes sense, as you'd want the gates to close early enough that idiots won't be tempted to slip past the oncoming train.
    • Rule of Cool.
    • Doc traveled to 1985 away from Marty's field of view, triggered the crossing gates, traveled to some arbitrary point in time, went to the railway crossing, then traveled back to 1985 precisely as the crossing gates he had already triggered came down. In short, he went through a hell of a lot of effort just to make an entrance (but what an entrance!).
      • It could just be a fluke or a malfunction, or maybe the disturbance from the time travel or the appearance of the DeLorean set off the motion detectors (or even caused a malfunction).
      • This has always bugged me too, but the way I look at it is simply that the level crossing had a random glitch that just happened to coincide with Doc's arrival. Level crossing malfunction is actually more common than you'd think. It wouldn't be impossible for the crossing to activate randomly based on malfunction or a dispatcher pressing a wrong button or something like that. As noted above, it's mainly for dramatic purposes, but for an in-universe response, either of these are probably the best you're going to get.
    • Judging by the popping sounds, the time machines may partially integrate back into the physical world before they actually appear, thus setting off sonic booms... not solid enough to hit objects, but solid enough to cause air displacement and thus the pops, and then the big displacement that blows stuff back when they get all the way there. But that still might be solid enough to trigger the railroad gates' motion detectors.
      • Also, since it was a 100-year jump, the longest the DeLorean had ever made (that we know about, at least), the sonic booms were far enough apart that, and this is a stretch, the gates could have been triggered manually by an operator (likely holding the Idiot Ball). Compare the last jump to the first one with Einstein, which was only a minute, and thus, sounded more like three firecrackers going off in quick succession.
      • Perhaps traveling through time creates local electromagnetic disturbances several seconds before the visible/audible pyrotechnics.
  • So when Marty pretends to be Darth Vader hailing from the planet Vulcan to scare George into going out with Lorraine, that inspires George to write a story about it later. However, after seeing the Star Wars and Star Trek franchise used two things that he would have used in the story does he ever wonder if they too were visited by the same alien? if so, would he try to get in contact with the creator of that franchise to talk to them about that only to be laughed at?
    • Vulcan is a Roman god, so the name would be likely to be used for a planet anyway. Star Wars came out twenty-two years after 1955. If you heard a name once, would you remember it after twenty-two years? Okay, maybe if the person who told you it was an "alien" invading your bedroom, but it's still conceivable George forgot the exact name.
      • And before anyone asks: no, the Vulcan salute wouldn't give it away, either. Leonard Nimoy drew on his Jewish background and the hand gestures used by rabbis in synagogue ceremonies to incorporate that into the character of Spock. The gesture, in other words, is common, not specific to Darth Vader from Planet Vulcan.
      • To add to this, there was a minor craze in science fiction in the early-mid twentieth century in imagining a tenth planet in the solar system, and given the tendency for naming planets after Roman Gods 'Vulcan' more or less stuck; Star Trek is the obvious example, but Doctor Who also featured this idea a few times around the same time (one of them being the first story Patrick Troughton appears as the Doctor, incidentally), and I think there were a few other examples floating around; point being, George McFly being the sort of sci-fi nerd he was, would probably be aware of this and not think anything was out of the ordinary; he'd if anything just assume that they were based around an actual planet called Vulcan.
    • By the time George has published the science fiction story which is (presumably) based on his 1955 experience, Star Wars has already been out for almost ten years. It's quite possible that he was saving the Darth Vader name for that, but then when Star Wars came out he thought "Dang it, some one else used it first" and changed it.
      • It's even possible that George no longer believes the thing really happened, but still considers it a fine yarn on which to base a novel.
    • Perhaps George waited so long to write the book because he was afraid that Darth Vader the Vulcan would be pissed if he blabbed about his "encounter", and only did so because other writers had successfully used those names without interplanetary repercussions?
    • I like to think that sci-fi writing George Mc Fly thinks that George Lucas encountered the same alien and used the Darth Vader name himself.
    • Or George as a science fiction writer himself might have befriended both Marvin Roddenberry and Marvin Lucas and helped their struggling cousins out with their own series by providing the names of Darth Vader and Vulcan.
  • Ok, so Doc couldn't change the letter he sent to Marty otherwise it might create a paradox. But why didn't they think to get themselves the supplies they needed AFTER they escape 1885 a la Bill & Ted? I mean, they have a time machine. All they have to do is, say, open that cupboard over there and, hey, a full gas can and new fuel line! Now, all they have to do use those to get back to 1985, buy a gas can and fuel line, then travel back to 1885 and leave those things for their convenience. Simple! Of course, there goes the plot...
    • They could only put that into effect after they got back to 1985 and if they're already back anyway, what's the point?
      • And it would * still* involve a paradox. Like I said above, though, all time travel into the past necessarily seems to by definition anyway, but that's another story....
      • No, it's not a real paradox. It's a causal loop (i.e. A causes B, which causes A), which is weird, but logically consistent. Basically this would be invoking Retroactive Preparation.
    • Obviously, Bill and Ted trump Doc and Marty when it comes to time travel jujitsu. "Excellent!"
    • In seriousness… Retroactive Preparation only works if it worked if it will work, and it doesn't if it doesn't if it doesn't. Characters in time travel stories don't need to be able to literally cause their own future selves to save their lives at any moment merely by hoping they will. Would it really be that "mysterious" if a character in a time travel story says "I strongly intend to eventually travel back to now and put a million dollars cash into this briefcase!", then opens the briefcase and sees that it's empty? Obviously, the briefcase being full or empty is the writer's prerogative, but there's a pretty good argument that "full" is less likely (and real-life experience certainly attests to that!). Of course, that could have been an interesting thing for the characters in the movie to try, but there's no reason to assume it would work.
  • I'm bothered by the "Save the Clock Tower" foundation. It was struck by lightning, a natural accident. How does that make it worth keeping broken?
    • I believe the Mayor was planning to replace it with an entirely new clock. Since the old one had been around for 100 years, some people just wanted to keep it for the sake of tradition.
    • Meh, people create activist groups for all sorts of silly reasons. Do we really need a campaign for English spelling reform?
      • Yes.
      • Wy dose we hav to spel good?
    • From what I remember, in one of the old scripts it said they were religious fundamentalists who didn't want the clocktower changed because God struck it with lightning and wanted it broken, or something like that.
    • It's a local historical point-of-interest. Granted, a point of interest to maybe only a small handful of people, but people have organized protest over smaller things.
      • It is important to preserve historical artifacts for the sake of preserving historical knowledge and for the understanding and viewing of future generations. Besides, it was probably the closest thing to a tourist attraction the town had.
    • It hadn't just been broken — it had been broken for 30 years. No one probably would have cared if they had tried to replace it back in 1955. As for why they didn't fix it in 1955, we'll have to suppose that either the city had budget problems, the plans got lost in committees, or no one thought it was especially important at the time.
      • Or nobody who had the authority to fix or replace it noticed.
      • I thought that the protest foundation were trying to get the clock fixed so that it would work again, not just preserve it in the same broken state it's been in for 30 years.
      • No, they wanted to keep it broken.
        "We at the Hill Valley Preservation Society feel it should be preserved exactly as it is."
      • This is not unheard of in Real Life. The old Christchurch Railway Station's clock (well, one of them) has been left to read 4:35 as a reminder of their earthquake.
  • How on earth does Doc control his height and altitude in the hover-converted DeLorean? Surely we should see him doing more than merely turning the steering wheel—that should only turn him left or right. Shouldn't there be an extra lever or something somewhere?
    • maybe by additional foot pedals?
    • Or pressure pads in the steering wheel that act sort of like a non-obtrusive version of the wingflap controls on a model plane remote control?
  • Here's one: why is Doc suddenly in such a rush to destroy the time machine after the rather minor incident in 2015 with Jennifer? I would understand his reasoning if he'd made the decision after seeing the horrors of 1985-A, but the Jennifer incident? That was the nail in the coffin for all time travel?
    • Doc Brown is a pretty smart guy. I'm sure after the "Jennifer incident" he immediately realized the full, horrifying implications of meddling with the timeline.
    • Don't forget that Doc spent quite a bit of time in the future before returning to 1985 to get Marty and Jennifer, so there's no telling what adventures he had. This troper recalls a Fan Fic that details Doc running into some trouble with a gang in the future over his stockpile of plutonium from 1985.
      • Doc was probably just finally accepting what he already knew (or thought he knew) in his heart. It took more straws than one on the camel's back to make that happen. I mean, he did invest thirty years of his life in the thing, you know.
      • It was the first time any of the dangers he'd run into resulted in a situation that he thought might have placed the entire space-time continuum in mortal danger. If that isn't reason enough, I don't know what is. (Of course, all time travel by definition entails paradoxes, so I guess some of them are more dangerous than others...?)
  • Christopher Lloyd went from JIM IGNATOWSKI to Doc Brown. That is all.
    • There's an episode that shows what Iggy was like in college. Maybe in the BTTF universe, he was never introduced to drugs.
    • In the Gale/Zemeckis FAQ for the trilogy, one of four possible answers they propose for Doc acting like he's forgotten many details in 1985 that he learned from Marty and other things in 1955 is that he experienced a memory loss in the years between from all the hard drugs he took as Reverend Jim.
  • Why do the Libyan Nationalists have a hippy van?
    • Because it was cheap and they could pay cash for it.
    • It's a Volkswagen! Those things are reliable. Just like AK series rifles. Oh, wait...
    • Reverend Jim will provide.
    • The terrorists are hippies.
  • If The Punch back in 1955 caused Biff to become a nice guy/complete wimp in 1985, why did he become, well, like his teenaged self again in 2015? Y'know, treating "Marty Jr." the way he treated George as a teenager and trying to alter history to make himself rich and powerful and all that.
    • It was 60 years later. He went from a teenage bully to a wimp, probably getting bitter over the years. He also knows that most people, like Marty Jr., aren't going to fight back when he bonks them with his cane. He's 77, fer cryin' out loud. Screw Politeness, I'm a Senior! and all that.
    • It was probably just George that he was ridiculously nice to, he's probably scared of him because he knows he packs a mean punch when backed into a corner and/or he could well report him to the police for his attempted rape. Anyone but George (even his grandson) is fair game however. Not to mention the fact that he's probably seen Marty Jr. around town, and his worried that he's going the same way that George before he manned up, or the same way Marty Sr. has gone, so giving him a bit of friendly advice is for his own good.
      • Supported briefly at the end of Part III when Marty goes to get his truck (so he can drive to Jennifer's house and awaken her). Biff starts to yell at him as a "butthead," but quickly falls back into the meek submissive role once he recognizes it's Marty.
      • Of course it's kind of amusing that despite falling back into his old gruffness, Biff was trying to be a nice guy there... he thought someone was messing with Marty's truck and was going to run them off. But the whole personality thing may simply be a sign that Biff's fortunes have actually improved as much as George's have from the time-tampering... in the original timeline, he was a supervisor at someone else's company, relying on George to do his work for him, and was a constant jerk because he didn't have to learn social skills. In the new timeline he owns his own business, and has learned to get along with other people, even if he has to act a bit phony to do it.
  • Did the clock tower in the original movie have a second hand? If not, how did they know the exact time the lightning would strike the clock tower? It seems to me that Doc and Marty would have had to have figured out a way to make the DeLorean hit the wire and remain attached to it for around sixty seconds. Otherwise, the lightning would strike too soon or too late to do any good.
    • You know... If you need to do that, you should put a metallic grid over the De Lorean, like the bumper cars have, connect the grid to the clock tower, and have Marty run for a time at 88MpH until lightning strucks and it's powers is chanelled to the grid, and from the grid to the De Lorean. But that would spoil the awesomeness
    • The flyer said the lightning struck the clock tower at precisely 10:04 pm. That is, 10:04:00 pm. Yeah, a Contrived Coincidence, but there it is.
      • A car traveling at 88 MPH equates to a speed of 129 feet per second. That would mean that Marty would have to be really, really precise.
      • In the defense of this theory, the producers mentioned a being that controlled space and time. And if that were the case, the being would have made things line up perfectly so that Marty reached the clock tower at the precise moment lightning struck it. Note that had he started going when the timer went off, he would have been late.
      • Maybe that wire that the De Lorean hit was more than just a simple wire. Maybe Doc had rigged some fancy gadget on the side so it would (somehow) continue to hold electricity for a second or two, and thus the timing didn't need to be perfect.
      • Also, lightning actively seeks out the most conductive available pathway between ground and clouds. Even if the timing wasn't absolutely perfect, and it had to jump a gap between the hanging cable and the hook on the DeLorean, it'd do so as long as that was a cleaner conductive pathway than going straight through the clock tower's superstructure.
  • Hmmm. Another thought. At the end of the first movie, Marty makes it back to 1985, watches Doc get shot, and then watches himself go backwards in time. We'll call the one who watches himself the TP Marty, and his counterpart the LP Marty. Anyway, the implication is that TP Marty has now arrived at the far end of a Stable Time Loop. But logically that can't be so, since the future TP Marty has arrived back to is different from that of his counterpart - the ripple effect has made his life great, and his father always stood up to Biff in this timeline. So what past does the LP Marty wind up in? Does LP Marty just hang with Doc for 7 days and then make a perfect run back to the future? And when he does, does he replace the TP Marty? My head! Argh!
    • This was already covered above with the question "Presumably there's a version of Marty who grew up with an assertive father. What happens to him?"
    • I recall an article that appeared between the first and second films that looked at this. Basically, LP Doc knows what happened first time round so he has ensured that there is a plentiful supply of plutonium in the car. Thus when LP Marty arrives in 1955 he simply reloads the flux capacitor and returns to 1985. However since he never interacted with his parents, George remained Biff's punching bag and thus LP Marty appears in the original 1985! His family is disfunctional and, worse, Doc is dead (because he never got the note in the past). As they said in the article, no wonder they made the movie about TP Marty!
  • How come we don't see cops all over the railroad tracks at the end of the third movie? The engineer whose train ran over the Delorean would've surely radioed in about the collision, so there ought to have been an immediate police response to determine if anyone had died. And even though no bodies would be found, a criminal investigation should've followed, to arrest the idiot who was driving on the tracks and risking a catastrophic train derailment.
    • The engineer couldn't have seen Marty well enough to recognize him in a line-up. What's he going to report? "Some kid in a cowboy outfit"?
    • Then the VIN on the broken-up DeLorean's parts should led the police to Doc, not Marty. Which is even worse, because Doc's disappeared, and Marty's the only person in 1985 he spends much time with, so he could come under suspicion of having killed Doc Brown and destroyed the DeLorean to get rid of evidence. A broken wrist could be the least of the problems Marty still has to avoid, if Doc's returned to 1885...
      • What possible reason would the police have to suspect Marty of murdering Doc? There's no motive and no evidence. A lawyer from the mall could rip that accusation to shreds.
    • Even Doc could be in trouble if the police investigate the train collision. Could there still be any traces of radiation on the car's pieces, from the plutonium and/or Mr. Fusion? Did he make references to his dealings with the Libyans in his research notes? If Doc ever shows himself in 1985 again, he could find himself branded a nuclear terrorist!
    • Authority figures don't seem to exist in BttF. This seems to be the case in a fair number of 80s movies — The Karate Kid is another one that comes to mind. I imagine there's a trope for this, but I don't know the name.
    • What bothers this troper is why the train which smashed the Delorean didn't even stop? in the REAL WORLD a train that smashed a car to smithereens on the tracks would by law have to stop and wait until authorities arrived, otherwise the engineer would be guilty of leaving the scene of an accident.
      • Real world explanation is that hiring a train to both crash into a car as the stunt and then leave it standing there would probably be expensive and take up a lot of space in the scene that would have to be worked around. In-universe, it's probably stopped a bit further up the track. It's a pretty big freight train going at full speed through a traffic interchange towards a bridge, after all; it takes some time to safely come to a full stop. Alternatively, maybe the engineer's just an unethical jerk; after all, people are supposed to stop at the scene of an accident but since it's not a binding physical law of the universe that they do, plenty of people just drive off anyway.
    • RE: points 3 and 4; remember, Doc has business to conclude in 1985, which is partly why he shows up at the end — he has to collect his dog and give Marty the picture for a start. Chances are, he's probably smart enough to learn of / anticipate both these issues and make suitable arrangements for them. To cast suspicion off Marty, all he has to do is plant something (a note in his handwriting or a video will or something) which reveals he's leaving town and gets Marty off the hook for any suspicions of that nature. As for being branded an international terrorist — well, that's in 1985, and he's not going to be living in 1985 any more (or any one time, it seems), so what difference does it make?
    • The police probably hadn't gotten there yet. But they'll find a smashed-up car whose VIN they would trace back to an eccentric Mad Scientist who seems to have suddenly disappeared. They'd probably conclude that Doc Brown finally snapped, put the car on the tracks and committed suicide.
      • They wouldn't suspect suicide unless they found human remains at the crash site. Which they wouldn't, since no one was in the car.
  • It bugs me, but how in the world would have Doc and Marty known one another in the first place? They are not exactly what one would call similar. One is a Musician, the other is an Eccentric Scientist Who Travels in time. What would they ever have in common? Or maybe I am just forgetting some important detail I can't seem to find anywhere in the movies?
    • An early version of the screenplay explained the Doc originally hired Marty to work for him as an after-school job. The filmmakers cut this because they had a lot of exposition to get through in the first film and didn't think that bit of information was especially important. And they reasoned that kids are naturally drawn to eccentric people anyway.
    • Word of God has also said that the fact that Doc has a super awesome human-sized guitar amplifier at his place provides a plausible reason for a wannabe rock god like Marty to befriend him.
    • Well, at least in the modified timeline Doc has a reason for seeking Marty out, and the guitar amplifier might have just been a way of forging a friendship between them. Maybe the reason they became friends orginally was because the timeline needed them to.
    • This troper remembers a fanfic that said he met Marty then he crashed into his trashcans after he lost his grip on a car.
    • Simply because Doc knows he'll have to befrend Marty at some point from meeting him in 1955. Doc is probably the one who sought Marty out, so that there would be no major paradoxes.
    • Word of God is right here. Turns out that Marty was just a curious kid circa 1981, and wanted to see this crazy inventor who everyone told him to avoid. Doc found Marty's curiosity to be heartwarming, and hired the lad on as a part-time lab assistant.
      • As a side note, for many years there were rumors of a script for a prequel TV movie called Back to the Beginning, which would have shown how Marty met Doc.
  • When Marty writes the letter to Doc in the first film, why does he write "Do not open until 1985" on the envelope? First, there wouldn't have been anything wrong with Doc opening the letter right after Marty had left anyway and secondly, all it did was tell Doc that Marty was trying to tell him about the future, prompting him to tear it up.
    • Because (1) he wants to make sure Doc doesn't forget any important details, and (2) he's being a dolt.
    • If Doc had read the letter before 1985, he would've known that terrorists were going to shoot him, and it may have prompted him to never initiate contact with the Libyans, which would've screwed up the timeline. Marty should have gone further and should have written "Do not open until October 19, 1985," keeping the timeline intact until that point but still giving Doc a week to procure a bulletproof vest.
      • Did the letter say he was going to be shot? If so, I don't think it said the shots would all be in the chest. Doc was really taking a chance by wearing the vest. Even if they didn't shoot him in the head, they could have shot him in the arms, groin, or legs, which may have still resulted in his death or serious injuries.
      • The AK-47 assault rifle on full auto kicks like a mule on amphetamines. The terrorist had it pointed at Doc Brown while set to full auto. Hence, he aimed for the biggest part of the body: the chest.
      • Few people ever shoot at such small targets. Everyone who knows how to use a gun knows to shoot at an object's center mass. Of course, there's still the chance that they'll miss and hit his head. But anyone who would knowingly design and build a machine that could theoretically create situations where a conceivably universe-ending paradox is possible has got to be more than a little reckless.
      • I'm not sure I know what you mean. As a person who has seen what bullets do to human flesh, I don't think I would entrust my life to a vest when someone is firing an assault rifle at me. Some people fire at "6 o'clock mast." You aim tends to creep upward at night. Also, an AK-47 has significant recoil, which causes the barrel to climb. Firing from a moving vehicle is erratic and unpredictable. I'm just saying that if I'm a six-foot-tall man, I'm not going to trust my life to a single piece of protection that covers around one-third of my entire body. Plus, Marty didn't see what happened after he goes back in time. How does he know the terrorists wouldn't go back and light Doc on fire? In summary, Marty's warning was vague and Doc's precautionary measures were too limited.
      • You're also not a character in a movie.
      • Guys. It doesn't matter. No 1985-era concealable body armor vest could have possibly stopped a full magazine of AK-47 rounds from thirty feet. Even a fully-reinforced 2000s era SAPI rig would have problems with that. If the Libyan has been firing an Uzi (with its much lighter ammo), maybe...but its clear that the Libyan is firing a much longer assault rifle, at point blank range. (Cracked even snarked this exact scene.
      • Concealable under normal clothes, maybe. Doc was wearing a bulky, baggy radiation suit and didn't need to be doing a lot of dextrous maneuvers. He might have put multiple steel plates in the thing (or lead plates, to help with radiation shielding while he was at it).
      • This is Doc Emmet Brown we're talking about though. He's got this letter in his possession for at least thirty years, easily time for him to spruce up an ordinary bulletproof vest with something with a little more staying power.
  • Why don't the fire tracks left by the Delorean in the beginning of Part 1 burn Marty and Doc when they're standing right in them? Are they supposed to be in the same spatial location, but a different time? If so, how come 1955 Doc specifically avoids them once he's sent Marty back to 1985?
    • I'm guessing that the only reason they appeared to be standing almost right in the midst of the flames was a Special Effects Failure.
    • It could also be because that wasn't actually fire. 1955 Doc thinks this, and avoides them, but this is because they look like fire. They could infact be holes in the space-fabric left by the De Lorean. Of course, this is only speculation on my part.
      • It probably isn't fire. When Doc gets sent back to 1985, the "fire" is actually visible in the air for a few seconds.

  • Didn't George ever wonder why his son bore such an uncanny resemblance to his wife's ex-boyfriend? Or that "Calvin Klein" would become one of the most well-known names in the fashion industry? Or for that matter, how both Gene Roddenberry and George Lucas somehow managed to borrow ideas from his private notebooks?
    • Obviously, George would assume that the same alien visited Roddenberry and Lucas.
      • His wife's ex-boyfriends tell them that tey will have a children that at eight years old would burn their carpet. THEN they knowed the truth!! But teenagers just need their space and live their lifes.
    • His wife's ex-boyfriend was someone she had only known for a week, neither of them would have ever seen any sign of him after that, and Marty was born more than 10 years later, after two other kids. Maybe it would look like a bizarre coincidence, but anything more than a coincidence would be just as implausible.
    • Marty returns to 1985 ten minutes before he left. He had to run at least two miles in those ten minutes to reach the "Lone Pine Mall" when Marty goes back in time. How did he do that? Sure, he was breathing hard...
      • If there's something very important waiting for you at the end of those two miles (such as saving your friend's life), then it's not impossible that you'd run fast to get there; adrenaline would probably get you through it.

  • Why oh why did no one, over the course of five years, among any of the thousands of people involved with the trilogy, ever inform Gale & Zemeckis or any of the actors of the correct pronunciation of "gigawatt"?
    • People probably didn't know at the time. They probably thought it was a derivative word from "gigantic."
      • Most people know the correct pronunciation today either because they heard how Back to the Future mispronounced it, or because the term "gigabyte" has become widely known due to the advancements of modern computers in the last decade or two.
      • "In the film Back To The Future the term is pronounced "jiggawatt" in reference to the 1.21 GW of electricity needed to power the fictional Delorean time machine. Though obscure, the "j" sound is still an accepted pronunciation. — The Other Wiki
      • The movie's science adviser had the habit of pronouncing it "jiggowatt" (which, as noted, is technically acceptable). Nobody in the case or crew realized that the science adviser was using an obscure pronunciation.
  • A number of questions related to the first film, brought up by comedians Chris Hardwick, Mike Phirman, and Matt Mira, between two Internet articles and a podcast:
    • Why does Marty only set the time machine to give himself ten minutes to save Doc's life upon returning to 1985?
      • Because Marty figured he'd be able to drive over there and warn him. But that would have caused a time paradox, which is exactly why the De Lorean failed. That, and Truth in Television.
      • It was Marty, however, who made the choice as to how far back he'd travel. Why not an hour? Why not a day? Ten minutes is not nearly enough time; even if he had made it there in time to see Doc (and his other self, and there's a time paradox for you), it's not like he could have expected Doc to simply have a bulletproof vest on hand.
      • Two miles in ten minutes to drive somewhere and shout "Doc, in a few minutes you're gonna get shot, get out of here now!!" is easy if you're in a rather fast car in the early hours of the morning with little traffic to impede you — he's not expecting the car to break down, remember. A day or an hour, and he risks bumping into himself or hanging around and losing track of time somehow, and although he's not exactly the sharpest stick when it comes to thinking fourth-dimensionally he's probably had enough time travel-related headaches in the past week to decide to make this particular instance as simple and painless as possible.
    • What experiment is Doc conducting where he's elated that the clocks are running 25 minutes slow? Is he just messing with Marty? How does he know Marty would be there anyway?
      • How it is possible to (change time on the clock) for all clocks simultaneously, even from another place with remote? Doc tried it and it worked.
      • Wild Mass Guessing: Doc's been doing test firings of the flux capacitor in the room to see how it affects the spacetime continuum in a very localised way. If the clocks hadn't all gone off at the same time, he'd have known the flux capacitor itself was damaging spacetime in some way, since he'd very precisely attuned all of them to go off at once.
      • The vagueness is intentional. They're establishing Doc as a mysterious, possibly kooky fellow whose experiments don't seem to make a whole lot of sense. As long as it foreshadows that some time-related experiments are going on, nothing more is needed. I think it's probably best if we don't always know what's going through that strange old man's head.
      • I haven't been able to check it, yet... but is it possible that Marty inadvertently walked into an experiment that stopped time locally? It would explain the 25 minute disparity in the clocks, and why Marty managed to end up 25 minutes late despite only spending a few minutes there and having a watch. It would also explain why Marty's watch is wrong along with the others, and fits perfectly into Doc's field of experiments, as stopping time would be as interesting to him as travelling through it.
      • Perhaps Doc started out with a small, prototype time machine. It wasn't big enough to hold a person (or even a dog), but it was big enough to hold a clock. So Doc got a bunch of clocks and synchronized them perfectly. Then he sent each of them through the prototype time machine individually, comparing their times in order to confirm that the trip was truly instantaneous. Then he kept all the clocks for a while and observed them each day, making sure that they stayed synchronized. He wanted to make sure there wasn't some sort of time dilation problem, where a clock would experience time differently even after it exited the machine.
    • Why does George McFly dye his hair in the original, more pathetic timeline, but not in the improved timeline where he's a writer?
    • How did Doc get into contact with the Libyan terrorists?
      • The terrorists probably sought him out. There can't be many people in a place like Hill Valley who have the know-how to build a nuclear bomb.
      • Gale and Zemeckis say in the DVD materials for the box set that they thought of Doc as having probably worked on the Manhattan Project. If the Libyans did their homework then they would likely have heard of him, so either they sought him out and he took advantage of the opportunity or he used his credentials to his advantage and sought them ought with his hoax already in mind.
    • Why does Lorraine's father (Marty's grandfather) complain that another teenager threw himself in front of the car? Has this happened before?
      • Yes. It's an Oh, No... Not Again! gag.
      • I thought it was a sneaky comment about horny boys eying his daughter as she changed.
      • This has happened before. Lorraine met all of her previous boyfriends because they were trying to look through her bedroom window and got hit by her father's car. This also helps explain why Lorraine is so taken with Marty: she assumes he was looking at her as she dressed (and apparently she doesn't find this creepy; maybe she even sets it up on purpose) and therefore she assumes that Marty is already attracted to her. In fact...we can further suppose that Lorraine's father suspects that this is the case. Therefore, he tends to hit these boys with his car on purpose (not too hard, mind you) as a way of saying "stop being a peeping tom". He further describes Marty as "an idiot" at the dinner table, because he thinks Marty was peeping.
    • Why does the family just have Biff, who attempted to rape Lorraine, hang around and do auto detailing work for them (as asked earlier on this page)? Furthermore, why didn't they get him sent to jail?
      • It was The Fifties at the time, with different societal attitudes. Also, time heals a lot of wounds I guess (see Watchmen for details). And when Biff was polishing the car, the Mc Flys weren't at home. They were out playing tennis. Biff himself is also a changed man: possibly he's even apologised to Lorraine for the attempted rape.
    • In the new 1985, why is Dave in a suit and going to the office on a Saturday? If he has an office job that requires a suit, how come he still shares a car with his parents (as implied by his anger when Marty claims the car was wrecked)?
      • Maybe the people at his office carpool. And maybe he's working on the weekend because he has a Pointy-Haired Boss.
      • And maybe Dave does have his own car, but the family refers to the nicest car they own as "the car". Dave's upset because he won't be able to drive it occasionally on a date or whatnot. Or maybe the family simply hasn't particularly had a need for more than one car until recently... George probably works from home, Marty's sister is still in school (and maybe her mother doesn't want her having her own car for, ahem, reasons), and Marty himself is only recently of driving age. The altered Mc Flys are obviously well-off but that doesn't mean they can just go throwing money around on cars for their kids at the drop of a hat, and with an amenable situation maybe Dave's saving his money responsibly rather than blowing it on a great car of his own.
      • We also don't know where Dave works in his suit. If it's close enough to walk or at the other end of a good public transport route, he may not need a car very often.
    • As asked above on this page, does George McFly eventually suffer mental breakdowns when he sees "Darth Vader" on Star Wars, the Vulcan salute on Star Trek, and hear the music of Van Halen? Or does he just believe the alien visited the creators of those works, too?
      • This question has been addressed above twice.
  • So the "old" McFlys from Part III are George's ancestors, and unless we admit a massive Squick moment, we are assuming that George and Lorraine are not related in any way, shape, or form...so why does George's ancestor look exactly like his wife? ** shivers**
    • Word of God is that McFly men are just predisposed to be attracted to women that look like Lea Thompson.
      • Yes, Claudia Wells could pass for Lea Thompson if you squint really hard...
      • Elizabeth Shue, on the other hand...
  • Biff saw the flying DeLorean in 1955!!!
    • And the hoverboard. Other than freaking him out though, I don't see how that's Fridge Logic, more like Fridge Brilliance. Are you watching closely? His incredibly disturbed reaction to seeing the DeLorean in 1985 ("What the hell is going on here?") probably made him remember that he saw it in 1955. He has a good memory even when old, as evidenced by 2015 Biff ("The manure! I remember that!"). By 2015, when he sees it for a third time and eavesdrops on the Marty/Doc conversation he finally has the solution to a sixty year old problem: how he was able to see a flying DeLorean, an unusual car even without the hover conversion, on three seperate occasions in his life ("So Doc Brown invented a time machine"). Of course you could argue that 1955 Biff only saw the DeLorean after Marty and Doc travelled back to retrieve the Almanac and hadn't seen it at the start of the movie when only Marty went back to 1955, but even so; he saw it in 1985 and again in 2015 before any serious changes were made to the timeline, creating 1985-A by having 2015 Biff travel back to 1955. Seems like he would have come to the same conclusion either way. If that isn't Character Development I don't know what is; he goes from a dumb kid in 1955 to an Evil Genius old man in 2015.
      • The Biff we see at the beginning of Part II isn't a part of a Stable Time Loop...he's only merely freaked out by seeing a DeLorean fly into the air and explode. Remember, in this trilogy, things happen from Marty's (and the audience's) POV; ergo, this Biffnote  doesn't have memories of a flying DeLorean in 1955 (or, for that matter, a second manure truck crash) because those things haven't happened yet.
    • Watch the tunnel scene again. 1955 Biff does not get a very good look at the De Lorean. He's looking up for exactly four seconds, during which time the POV shot shows us something unidentifiable as a De Lorean (especially since the car hadn't been invented yet) and looking not so much like a car as an air-roving Hunter-Killer from the Terminator movies (although they hadn't come out yet either). It's possible that 1985 Biff remembers seeing that irritating Calvin Klein kid get pulled up into some weird aircraft or spaceship, but he doesn't have any way of knowing it's the same vehicle he sees for a longer moment, from the front, in broad daylight, thirty years later. And if he doesn't recognize Marty as looking like Calvin Klein (which he theoretically might—just because he hasn't said anything doesn't mean that he doesn't—but let's apply the principle of conservatism here), then chances are he doesn't remember the Doc Brown voice (which had shouted only about three words) very clearly either.
      • The only headscratcher here is: In the span of a week, Biff went to being the King of the Valley, to see as a foreigner with funny clothes that Pwned him, then the same guy befriended the local Butt Monkey and made him a confident and assertive man that punched him KO. and THEN the same guy with funny clothes robbed him from a magical Sports Almanac, who was incidentally using a flying board, and finally he was helped by what looked as a frigging 'SPACESHIP'. And then, the guy dissapeared and never was seen again. HOW is that Biff didn't commited himself to an asylum? How is that he remained in Hill Valley and didn't hid himself in a cave for the rest of his life, for fear of "Aliens with a Lifesaver Vest"?
    • The first few things are demoralizing, perhaps, but not really the kind of thing that intensive psychiatric therapy is called for. The "aliens with a lifesaver vest" thing is a bit more of a potentially destabilizing thing, to be true, but the very fact that 1985!Biff ends up a completely spineless wimp is perhaps indicative that his experiences did indeed take a bit of a toll on him, but thirty years is also a pretty long time — time enough to more or less come to terms with things, at least.
  • Rule of Cool of Flying Car overrides Fridge Logic perhaps, but when Doc went in to have a hover conversion fitted to the DeLorean, presumably a very extensive modification judging by the amount Goldie Wilson III says it costs, did no future mechanic notice the flux capacitor, time circuits switch and the huge LCD readout panel mounted to the dash with the labels "DESTINATION TIME", "PRESENT TIME" and "LAST TIME DEPARTED" - not to mention the converted nuclear fission reactor on the back?
    • I always assumed Doc made the hover conversion himself. He did the same for an entire freaking train engine in 1885...
    • No, he went to the future before appearing to Marty. He had the hover conversion done then. Although that leaves the question of why the train time machine still runs on steam.
      • He could have done it himself in the future, after learning how from future people. The two things are not mutually exclusive, folks.
    • Rule of Cool.
      • Fridge Brilliance, again. The only thing needed for a steam powered engine is something to burn, like say wood, something that would be plentiful in any time period.
    • Doc installed all the time-travel stuff into the car in the first place. If he needed somebody else to perform the hover conversion, he could probably just take out all the time-travel stuff, get the car converted as if it were a normal car, and then re-instal the time-stuff himself.
      • Possibly he told the mechanics who did the conversion that the car was needed as a prop for an upcoming scifi/comedy movie about a time machine. Don't touch those fake dials and gizmos, please, the prop department worked really hard making those look like old antiques from the '80s.
  • Here's something I've always wondered, and I'm surprised it's never been mentioned yet. Why does 1955 Doc have such a colossal freak-out at the end of Btt F 2/beginning of Btt F 3 upon seeing Marty again right after sending the past Marty back to 1985? He knows all about the time machine by this point, so why would seeing another future version of Marty cause him to go into shock, pass out, and then act in denial of Marty's existance until he shows him the letter from his future self?
    • He had just spent a whole week wrapped up in that scheme, only for it to come to naught (as far as he can see) the very moment it had succeeded. Anyone would be tempted to be in denial after that. Besides, Doc is an excitable fellow.
    • In addition to the above, Doc's probably scared that the whole timeline is collapsing around him. Send a guy into the future and suddenly he's standing right next to you? Something weird is going on...potentially something bad...
  • After the time machine was destroyed in Part III, one would think that eventually someone would come by to see if there were any bodies in the rubble, and to clean up the scene. The problem is, there are several parts of the time machine that were either unique to it (the flux capacitor and time circuits) or were borrowed future technology (Mr. Fusion and the destroyed flying circuits). Does it stand to reason that someone may have found, say, the Mr. Fusion device, and reverse-engineered it to become the "new" creator of the Mr. Fusion? Kind of like what happened in Terminator or Star Trek IV.
    • What are the odds of someone who would know what to do with such an elaborate kind of mechanism chancing to come across the rubble before it was cleared? Or that the pieces would be in any condition to help them? It had been hit by a train, most of it was probably crushed and mangled beyond recognition, and the first responders — most likely police and emergency crews — would most likely just assume it was some kind of fancy electronics.
  • I don't know enough about science to answer this myself, but I've always wondered: can a single lightning bolt generate 1,210,000,000 watts of electricity? Or can the small amount of plutonium seen in the first film? I wouldn't know, but it sounds like an awful lot....
    • According to The Other Wiki, it could send hundreds of Deloreans Back To The Future. "The average peak power output of a single lightning stroke is about one trillion watts — one "terawatt" (1012 W), and the stroke lasts for about 30 millionths of a second — 30 "microseconds"."
    • Fissioning one kilogram of plutonium can produce 20000 megatons of energy, which is about 100 petajoules. So, in theory, it could keep on producing 1.21 gigawatts of power for about 3000 years.
      • Uh, no. Try 18.5 hours, if we're assuming pure Pu-239 and fissioning 100% of it (in reality, some of it would be transmuted into heavier isotopes and some would remain Pu-239 after the reactor has gone subcritical due to fuel depletion).
  • Why does Doc Brown need a disguise for showing himself to Marty? Marty has seen him younger and thus would recognize Doc 30 years younger, so that seems kinda pointless?
    • It was a handwave. Christopher Lloyd, when the first film came out, looked like Doc Brown in 1955. They put make-up on him for his 1985 scenes to make him look older. When it came time to do the sequels, he didn't want to be put in make-up to look older for he whole time, so they did the "rejuvenation therapy" excuse to make him look young again, and threw in the 'disguise' bit as a Lampshade Hanging. Honestly, though, I always thought the joke was that he looks exactly the same regardless.
      • Ditto. If there was makeup involved, it was too subtle for This Troper to notice.
      • It's there, definitely (though it's probably more subtle than it should have been IMO). Plus Christopher Lloyd gives the same highly energetic performance as both Young!Doc and Old!Doc, and that throws people off. The hair is the most obvious giveaway. Old!Doc has stark white hair that he doesn't even attempt to tame, while Young!Doc's hair is neatly combed and still has some color to it. Also, Old!Doc is just a little more wrinkled and a little more haggard-looking than Young!Doc.
    • I also felt that this was more of a "just in case" choice by Doc Brown. He almost always takes extra steps to prevent catatrophic events due to the effects of his time travel, so this always seemed like Doc taking every available precaution, whether or not the risk was very high.
    • Rule of Funny — as noted above, the joke is that even after having thirty-or-so years of his life rejuvenated Doc looks exactly the same as he ever did.
    • Doc explicitly says to Marty that he's wearing the mask because he wants to avoid the surprise and confusion of older Doc disappear one day and younger Doc show up the next and all the resulting questions this would raise (such as "Doc? How come you look thirty years younger now?!") and ease Marty into accepting this when he feels they have some time. Of course, the effort turns out to be pointless because he looks exactly the same, but the logic's there.
  • Why are we 5 years out from the events of the 2nd film and still without hoverboard and flying cars? Seriously, Mattel needs to step it up.
    • We're getting there.
    • We destabilised the space-time continuum when fax machines fell out of popularity. Without the amazing development of having a fax machine in your cupboard, scientists have been unable to replicate the technology for flying cars, hoverboards, self-lacing shoes, and self-drying clothes. Some suspect this to be an conspiracy on the part of moviegoers in order to prevent the making of fifteen more Jaws films.
  • Why did Doc Brown get so upset with Marty over buying the Grays Sports Almanac, when in the first film he said he planned to get the results of the next 25 World Series?
    • He wasn't upset that he just purchased it, he was mad that he was concealing it because he was clearly planning to use it to make money. I don't think Doc Brown ever said he wanted to know the World Series results for that reason.
    • I think he was upset even at the purchase since he knows Marty too well and even possession of the book can lead to trouble (as the film proves), but yes, he never said in the first film that he intended either to gamble on any world series nor to bring back any future records or evidence of who would win them, only that he was interested in knowing, as I suppose many baseball fans would be.
      • I always assumed by that line, that Doc Brown was planning on watching the next 25 world series in person rather than looking up the results.
      • Also, at this point Doc doesn't have much experience in the ways of time travel. By the time he tells off Marty, he's lived through the first movie's chronological shenanigans and apparently had a few adventures besides. He knows what the consequences could be.
      • Or, he's telling off Marty but he's actually cross at himself for putting the idea in the boy's head to start with with that '25 World Series' bit.
  • When Doc is drunk in 1885 and explaining the concept of the automobile or "horseless carriage" to the other bar patrons, they express pure disbelief and act like he's crazy. But would people from 1885 really react this way? It's not the middle ages; they're used to locomotives, and it's not much of a stretch to imagine a locomotive that can work without a track. And besides, in 1885 people like Karl Benz were already designing and tinkering with the first production cars. This is like someone from 2095 going back in time to 1995 and heralding the invention of...the DVD. Most people would say "yeah I could see VHS tapes becoming obsolete soon," not "oh you crazy mad scientist and your wacky impossible ideas!"
    • The other patrons only think he's drunk, but still, that's their perception, so it's less "Oh you crazy mad scientist and your wacky impossible ideas!" and more "Oh that drunk guy is rambling about the future." Also, just because some people were designing and tinkering with prototypes doesn't mean a buncha cowboys out on the frontier are going to know anything about it. And the VHS to DVD thing is faulty, since technology has progressed much faster in the last 20 years than it has in previous eras of history, so that someone in the 1990s would have more expectation of one technology replacing another than a bunch of drunken frontier cowboys in 1885 would expect something they've never heard of or seen becoming so commonplace.
      • And even if a bunch of bar flies did know about the prototype automobiles being built back east, there was still serious doubt in the late 1800s about whether the concept would ever really get off the ground.
      • Haven't they been reading their Jules Verne? "Five Weeks in a Balloon" was first published in English in 1869 (and "Around the World in 80 Days" in 1873 (although it didn't actually take place in a balloon.)
      • It's a safe bet to guess that old drunk cowboys in 1885 were illiterate.
  • In the first movie when Doc and Marty are loading the plutonium into the Delorean, they are wearing radiation suits to protect themselves from the plutonium. However, less than 10 seconds later after Doc and Marty have taken off their headgear, Doc opens up the chest FULL of plutonium to put them empty jar back, exposing himself to a severe, if not lethal dose of radiation. All of this happens IN THE SAME SHOT. How could the filmmakers have missed this?!
    • The plutonium was in a tube like thing in the glass jar. When he loaded the plutonium, it was removed from the jar. The jar contained some sort of liquid, which I assume it protects the handler from radiation. If you notice, the liquid is still in the jar after the plutonium is inserted into the car. It was only during the transfer that there would be possible exposure.
  • We know that the DeLorean becomes very cold immediately after traveling through time. And vacuum tubes need to be warm to operate properly. In BTTF 3, Doc built the time circuit control tubes right on the hood of the car, and specifically said they were "warmed up" before sending Marty off. Shouldn't the tubes have shattered from the rapid temperature change immediately after Marty went back to 1885, especially with all the vibration from the off-road conditions at high speeds?
    • Dunno about the vibrations, but the "time travel freezes the car" thing is something the deliberately downplayed and dropped over the course of the series, presumably so they wouldn't have to spend time/money frosting up the car all the time.
      • It's true that they downplayed it, but it still happens. If you look closely at the DeLorean right after Marty is transported back to 1885 (just before he shouts "Indians!") you can see some frost on the car.
      • You can also see it in Part II after Marty and Doc travel back to 1955.
      • I have a theory that the only bits that get cold are the stainless steel shell of the DeLorean (having to do with the stainless steel helping the flux dispersal or whatever) and NOT the various electronic bits or other automobile parts. 1985!Doc probably knew this and figured the vacuum tubes would be safe. (I'd also wager that his 1955 counterpart packed the trunk with extra tubes and parts just in case).
    • Since time travel is precisely what is involved, there's no reason to assume the temperature change happens "instantaneously" even though it appears that way to the driver. Maybe, from the tubes' frame of reference, Marty (or whoever is driving) moves extremely slowly "during" the trip (which, after all, does last a hundred years, in a way).
  • After the events of the first movie, Marty, Linda and Dave ALL should have ceased to exist. The odds that Confident George and Lorraine would have sex at the same times as their counterparts in the Twin Pines universe, so that the same ova and sperm meet to create the same individuals, are astronomically improbable.
    • Some people theorise that time has a way of putting things into place - nobody cares if you step into an ant or bump into some guy and make them five minutes late. It takes the altering of distinct and crucial events to really change something, like when Marty stopped his parents from meeting.
  • 1985 Doc holds Albert Einstein in high enough esteem to name his dog after him. At the beginning of part III, however, as Doc is reading his letter he says something like "Please take care of Einstein for me." pause "Einstein?" Then Marty tells him its what he calls his dog in 1985. Doc gives this look that suggests he thinks it is a silly name. Why would 1955 Doc's opinion of Albert Einstein be so low?
    • My interpretation of that was different: upon first reading this (without scanning ahead to the next sentence), Doc thinks his future self used the time machine to bring the actual Albert Einstein to 1985. Naturally he would be rather surprised at that.
    • Yeah, that's pretty much exactly what's meant by that. Hell, if you want to get into WMG territory, the 1955 section takes place in October of 1955. Einstein died in April of that same year. For those few seconds, Doc is probably thinking, "He didn't die, I brought him to the future!" The look isn't that he thinks it's a silly name, it's that Doc is somewhat disappointed that he won't be hanging out with what's likely one of his idols.
      • Heck, forget idols, could have been one of his friends. It's implied in places that Doc worked on the Manhattan Project, he may have named his dog not after some far-off idol but a good buddy he'd been missing for awhile.
  • In the first film, Doc rigs up an alarm clock on the dashboard of the DeLorean and tells Marty to "hit the gas" when it goes off, so he'll reach the conducting wire at exactly the right moment. Not only were his calculations off (the car stalls until a few seconds after the alarm rings, yet Marty still hits the wire at the correct time), but it wouldn't even be possible for the calculations to be correct. It might have been possible to figure this out if the DeLorean had an automatic transmission, but we can clearly see from the first chase scene that it has a stick shift. Unless Marty is planning to get to 88 MPH in first gear, he can't just "hit the gas" and keep going. He has to momentarily release the gas to upshift - and this makes the run impossible to time with any degree of repeatable accuracy.
    • Actually, Doc's calculations may not have been incorrect. We see the Present Time on the time circuits reading 10:03pm a few seconds before the clock tower ticks over, therefore it is apparent that the clock tower was slow, meaning that the lightning did not strike at precisely 10:04pm. If Doc had used his own correctly timed watch to plan his calculations, his calculations would have given him a few seconds off owing to the difference between clock times.
    • How would Doc know how a car from thirty years in the future works? Given that Marty hits 88 miles per hour before he hits the wire (you can see the bottom of the car light on fire like it does when it time travels), then it's likely that Doc didn't know what the DeLorean was capable of.
    • There's also a variable in the fact they don't know at which second the lighting strikes the tower. One entire minute is one hell of a long time when you require a car moving at 88mph to be at a very precise location when a lighting bolt strikes. All in all, this whole plan runs on Rule of Cool, and had near to 0 chance of working considering the information the Doc had.
  • What sort of experiment causes all of your clocks to run twenty five minutes slow? Before you answer that, I point out that this was before the first run of the time machine.
    • I think it's meant to be left to our imaginations beyond hinting at the time travel theme. It's just a Noodle Incident.
    • This troper once read an interesting Epileptic Tree on a BTTF fansite that hypothesised that the Doc had been converting his clocks from sidereal time to solar time. It even had some math to back it up, and it guessed that Doc would eventually go home to reset his clocks to the correct time.
      • Supposing that the clocks were first sent as inanimate objects to test it before he sent his dog for the ride?
      • Pretty sure that's exactly what it was supposed to be. Just because that's the first time we see the time machine doesn't mean Doc hasn't tested it before. He is a scientist, he wouldn't bring Marty along to film if he didn't know if it was going to work.
      • Copied from above: Perhaps Doc started out with a small, prototype time machine. It wasn't big enough to hold a person (or even a dog), but it was big enough to hold a clock. So Doc got a bunch of clocks and synchronized them perfectly. Then he sent each of them through the prototype time machine individually, comparing their times in order to confirm that the trip was truly instantaneous. Then he kept all the clocks for a while and observed them each day, making sure that they stayed synchronized. He wanted to make sure there wasn't some sort of time dilation problem, where a clock would experience time differently even after it exited the machine.
  • Many fans do not live at USA at the first place, nor they live in the small Pasadena-like towns. Is there something special in lifestyle of this towns, that foreign Btt F fans can miss because they are not acquainted with US? First question: what's population of Hill Vallley? 20k? 10k? 5k? Second question: how can other parts of the town be called? Hills&Mills? Pine View?
    • Neither of those questions really would have an impact on one's understaning the movies. But here are a few Useful Notes. The centerpiece of Hill Valley is the Courthouse Square which, in many small towns, was the center of business activity. You will notice that the square is a lot dirtier in 1985. By that time, many small town squares were no longer important because (like Hill Valley) large malls had been built on the outskirts, usually former farmland. Availability of cars meant that more people lived in planned suburban developments (like Lyon Estates and Hilldale) and drove to work. Of course, the films are loaded with more cultural references than could fit here.
    • There's probably always stuff you miss when a film or TV show is set in a country you've never lived in. The best stories, though—like this one—render that more or less irrelevant to the enjoyment factor.
  • Just a minor thing that bugs me about that distant world of the future. Why would there be a thumb reader on both sides of the door, as shown when young Jeniffer can't get out because "there's no doorknob"? (unlike RL devices we have now, which usually have finger scanner on the outside and regular knob on the inside) Isn't that just a little weird that you need authorization to get out?
    • Not really. Similar safety measures have been implemented in stable facilities and suggested for mobile facilities and vehicles in Real Life. it prevents anyone who does manage to get in from jumping and running at the first sign of trouble, since they'd have to work their way through the security from the inside (assuming they hadn't simply blasted through the window or door or stolen the owner's finger).
    • It still seems odd for there to be one on a private house, though. Dangerous, too, if you think about fire safety.
      • Maybe everything's fireproof in 2015, or the system automatically lets people out if it detects a fire.
    • Perhaps it's to ensure that only authorized people (i.e. the residents, maybe even just the parents if it's a strict household) can let people into the house.
  • At the end of the first movie, why is Doc in such a hurry to get Marty and Jennifer back to the future to save their children? Chill out Doc, it's not gonna happen for another 30 years.
    • Currently Marty looks exactly like his son. Since he's 17, he's still maturing quite rapidly at that point. Doc doesn't know if Marty would be able to pass exactly for his son further down the line.
      • It can't have waited a few hours though?
      • Doc might have got himself locked into a 'San Dimas Time' way of thinking (i.e. the clock is always ticking and I have to get this done right away!); perhaps not rational, seeing as San Dimas Time doesn't seem to operate in the BTTF universe, but he's perhaps running on adrenaline a bit given the nature of the crisis and not really thinking straight.
      • Doc's watch is set to the precise 10/21/2015 time, and he's calculated all the events down to the moment. Remember when he looks at his watch when the weather changes, and remember how its alarm goes off when it's time to go intercept Marty Jr.? Doc imposed San Dimas Time on himself.
  • I know I know, Berserk Button and probably not thinking straight, but Marty is still a massive idiot for letting Griff get to him from being called chicken in 2015. The insult was meant for Marty Jr., so why does Marty even care? Or could he be taking the insult as a means of saying "nobody calls my son chicken!" ?
    • Pride is rarely rational. A personal example: When I was in drama club in high school I was never comfortable playing buffoonish, doltish, or silly characters because I had a very hard time separating myself from the character I was portraying. So when the audience would laugh at something I did on stage it felt like they were actually laughing at me rather than at the buffoonish character I was portraying. No matter how many times the cold and logical side of my brain told me that they were laughing at my character and not at me, it took me a long time to learn how to get over my pride and stop taking their laughter personally. The same thing is probably going on with Marty. Even though he knows Griff is technically insulting Marty Jr., Marty Sr.'s pride causes him to take it personally all the same.
    • I originally figured that he was thinking, "That's my future son being called a coward. That pisses me off!" The irrational pride thing holds true too.
  • Leaving Jennifer on a porch in 1985-A, with nothing but Doc's guess/hope that history will shift around her and she'll end up where she's supposed to. I understand why it was done from a story perspective - the ending of Part I forced them to bring her along, but they couldn't just leave her in the back of the DeLorean in a coma for all of Part II and III - but every other fictional treatment of time travel This Troper has seen says that she would have been lost in a timeline that's no longer accessible/doesn't exist. You don't switch time-tracks without a time machine, period. Since they were already re-shooting the ending to substitute Shue for Wells and add Biff's reaction, they should have just left her standing at the curb and saved a lot of trouble.
    • Possibly the act of travelling in a time machine renders her a certain level of immunity to The Ripple Effect, just as Marty and Doc are. That immunity is enough "chronological protection" to leave her asleep in an alternate timeline because God, The Dark Tower, or Peewee Herman will hold that timeline in existence long enough for Marty and Doc to try and shift it back from 1985-A.
    • Doc is confident, and being the guy who invented the time machine he knows enough about what will very likely happen that he doesn't have to guess or hope. Besides, it's the way things always work in these movies, the timeline changing around a person from another timeline. He's just reasonably predicting that to stay consistent.
    • The best thing I can say is that she was left in her porch in 1985. So when they changed the past, she woke in a safer 1985. Whatever misventures she could suffer in Hell Valley were erased. They are so lucky that the Delorean don't work like the Petrelli Time Travel with Caitlin!
  • Biff in 2015 plans to steal the sports almanac and give it to his 1955 self. Fine, young Biff has the sports results and bets on winning games... but how long would that last? Eventually the change in history, even minor, will ripple out. We know that Biff eventually made real money but a change to time could result in games eventually being played differently, making the entire almanac useless, and cutting into Biff's fortune if he bets on a game and the altering of time changes the results. That's not getting into the possibility that Biff could be investigated for winning a lot of bets in a row... sure, the book could make some easy money early on but the change that Biff would become that wealthy would be a slim one.
    • Why would the book not change when we're explicitly shown every single other piece of future documentation change when the relevant facts to it change in the past? The photos in the first and third film, the newspaper in the second, the fax from the second that changes in the third...Every single time something changes in the past, artifacts from the future change to reflect it.
      • The real problem is either the book shouldn't change at all, making it increasingly inaccurate, or it should cease to exist, because the Biff that brought it back in time doesn't exist anymore. It's hard to see how there's a middle ground, where the book correctly updates scores, but not the fact it shouldn't be there at all. The best option is the book doesn't change, and Biff might have interfered too much in one sport, and the book became inaccurate for that. So then he shifted his focus onto European soccer or something he'd never messed with, and very carefully kept from doing anything that could influence outcomes, like buying teams or meeting players or even flaunting his bets.
      • And again you're ignoring every other identical example of items changing their content, but not disappearing—starting with Marty's picture in the first movie, the fax from the second movie, the newspaper from the second movie, and the picture of the tombstone in the third movie. Why are you expecting the almanac to act completely different from every other 'object from the future with information from the future' in the series? Your unimaginable middle-ground is already, and repeatedly, explicitly shown as exactly how time travel works.
  • In Parts I and II, why do the people wanting to save the clock tower asking for donations? It seems they want the clock to stay as it is (unmoved since 1955), giving the money to the mayor would just be money that could be used to help replace it. Couldn't they have just asked Marty to sign a petition to save the clock tower?
  • Piddly question, but something I've always wondered about: How is Marty not in pain when he wakes up? In the real world, anyone who slept like that would have some serious shoulder and arm issues. Kind of disconcerting with the knowledge that playing guitar is Marty's favorite thing in the world to do.
    • If memory serves, he is seen rolling and rubbing his shoulder a few times after waking up, as if getting rid of some stiffness.
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