Headscratchers / Back to the Future

For Headscratchers related to Part II, see here. For Headscratchers related to Part III, see here.

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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?
    • Scrolling displays have existed for a while.
    • Most likely, the chronal display was an afterthought put together with spare digital clocks. He was more interested in making sure the prototype worked than in building a bigger control panel.
    • Also quite possible the time machine can't go back that far anyway. It might have an upper limit, though admittedly it didn't in the cartoon (where the display was also longer).
  • In the altered 1985 McFly 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?
    • The majority of 80s camcorders were supplied with RF adapters so that they could be connected to the antenna input of a TV. Even if Marty didn't have one, it would have been pretty easy for Doc to connect it up. Just a matter of tapping into a couple of wires inside the TV, maybe using some basic components readily available in 1955. Remember, the 1955 TV used essentially the same TV standard as the camcorder; when American TV introduced color, it was specifically mandated that the color format (aka NTSC) had to be backwards-compatible with the installed base of B&W televisions. This led to compromises that meant that NTSC wasn't as good as it could have been, but on the other hand, it means any modern NTSC video source can fairly easily be made to work with any vintage American TV. The same doesn't apply in (say) the UK, where the color TV system introduced in the 60s is completely incompatible with the previous B&W system.
    • 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 have 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 DeLorean 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 traveling back in time, but that's probably what he planned on doing.
    • Plus he isn't very good at thinking fourth-dimensionally.
  • 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?
    • Never mind 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 super-genius, 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.
    • He probably went with the vest so that it would look like he was killed so that when Marty went back, he would still think that he was killed and warn his younger self. There is the possibility that it might not work, but Doc's the guy who invented a time machine. He probably thought it was worth the risk.
  • 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 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.
    • It doesn't need to be in the same exact moment, anyway. He just needs to get the electricity of the bolt. If he wasn't at 88 mph at the moment, then the time machine gets its energy but he doesn't time travel, not yet; he does so so moments later, when he reaches it. And if he gets at 88 mph before reaching the bolt, no problem: he will get the bolt at 89 mph or 90 mph, and it works anyway.
  • 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.
      • The owner looks curiously at Marty while he's in the phone booth because he hears Marty's watch start beeping, but then he moves back to the counter and there's no evidence that he's actually aware that Marty has torn the page out of the book. His "Are you gonna order something?" cuts across a question from Marty and suggests that he thinks Marty is just a time-waster.
      • Why does Marty ripped the page? Because he had no pen available to take notes, and he's a dick. As for the owner, he asked Marty to order something when he had the ripped phone book page in his hands, and asking for the street in it. Of course that the owner noticed it. And he was clearly going to leave the bar just like that, so as said by the third poster, he is clearly not amused and wants some form of compensation.
  • 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.
      • Doc also isn't properly grounded if he's wearing common leather shoes that were available at the time, and voltage at it's most base level is a difference in potential between two points. Given that Doc was holding onto the wire when the lighting hit he and the wire were at the same level of potential with the wire having a definite path to the ground and Doc just being an outlier. Large wires also have very little resistance to them so almost all the current is going through the wire and Doc is getting hit with a much smaller amount.
  • 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.
    • Well, Doc can't be blamed for the existence of bolts of lighting, can he? He can simply said that it was an unexpected disaster.
  • 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 is George's supervisor, although I imagine George got the job first and was "pressured" by Biff to get him his job. Biff would then, like he did in high school, bully George into doing his work for him. Eventually this would lead to Biff getting promoted over George. It's a shit situation, to be sure.
      • 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.
    • Why does George keeps Biff working for him? Because he's a living trophy. Each time he sees him as his personal slave, he relives the point when he bravely took down the school bully and had his life changed. And why doesn't Biff try to bully George now? Well, being a bully in high school is one things, students are equals. Being a bully with your boss (the man who can get you fired) is a massively bad idea, for the same reasons that young Biff was not a bully with Strickland. It's even worse for an uneducated jerk stuck in a dead-end job, with no other people to talk to in case he's fired. Even a complete dumbass like him will be aware that he's in no position to try anything funny.
      • Its part of a subtle plot point that was dropped for the sequel, namely that people tend to forget what the past was really like. Its the same reason why Marty's parents don't recognize him as the kid who had such an influence on them despite only knowing him for a few days, in their minds he looks completely different. All George remembers about his and Biff's teenage years is that Biff was a bit of a bully who got handy with his girlfriend until George put him straight. He doesn't remember what actually happened anymore, he only has the vaguest recollection of youthful indiscretion. It helps that Biff changed so dramatically in the following years.
  • 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.
      • But he had it in the diner (he had to hide it from Lou when it beeped), so that means he must have lost it somewhere in town (maybe Lorraine took it off him), which could lead to a time paradox that destroys the entire universe.
  • 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?
    • Remember, though, Lorraine was a cool and popular girl in high school; she only became a loser after marrying George. And as we see in Part II, Marty's life, even after fixing his family, follows the same path.
    • 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 DeLorean is under RC control? While automatic was an option on the DeLorean, 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 probably 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.
    • When Doc is reading the flyer out loud for the first time, he mentions that lightning will strike the clock tower at "precisely" 10:04 PM. This means right when the clock changes over.
      • Except that the clock tower clock clearly DOES 'tick' between minutes.
    • Furthermore, even if it's 10:04.00000000-as many zeros as you want, that's the time on November 12th, 1955. Leap seconds have been added to account for irregularities in Earth's orbit ever since 1972. Does the DeLorean account for any intermediate leap-seconds between the origin and destination time-frame? Can it extrapolate for times before 1972 or likely leap-seconds in the future? Will Doc go to the end of time and get the definitive list of leap-seconds, leap-days, and other timekeeping aberrations for all of history?
    • Rule of Drama, Willing Suspension of Disbelief and Necessary Weasels, people. We can descend into pedantry-inspired lunacy of the failure of the writers to account for the exact millisecond that the lightning struck the clock tower, or we can just accept that "10:04pm" means the exact stroke of 10:04pm for the purposes of a dramatic moment in a science-fantasy movie and move on with our lives. Some Headscratchers aren't worth fretting over.
  • 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?
    • You're assuming that the mall/farm is farther from town than Lyon Estates. But if Marty's instinct was to get home, he wasn't necessarily heading towards town after leaving the farm.
    • 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.
    • Lorraine explicitly says "Your first novel!" when they open the box. George could have written short stories, for TV, movies or comic books and made money before a novel. Many classic Science Fiction authors got their start writing short stories for magazines like Astounding.
    • Alternately, many English majors and writers go into/start off teaching. George could've made a living as a college professor (possibly of literature or creative writing) while waiting for his big break.
  • 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. Part II shows that he's a bit of a gear-head.
    • 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.
    • A scene from the second movie shows Biff arguing with an auto detailer over the amount of money he's being charged for the repairs on his car after the first manure truck accident. That probably inspired Biff into pursuing that career.
  • Doc, having met him 30 years earlier, knows that Marty'll be accidentally 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?
    • Doc knows that, back in 1955, one time-lost Marty was sent to 1985. What would happen if he didn't send the 1985's Marty to the past? Well, it would happen that the 1955's Marty would appear anyway, and then... imagine him getting into his own bedroom and, instead of finding a girl of an Afro-American family, he finds another version of himself. Great Scott!
  • 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 DeLorean 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 DeLorean, causing a paradox. Regardless of that, he also needed to fool the Libyans or they'd kill him for real.
  • 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.
      • It just concerned me when Doc yells "IT WORKS!" all excitedly after the experiment. I was like... so there was a possibility that it wouldn't have worked?
      • Well... yes. It's an experiment. There was always a possibility it wouldn't have worked until he'd tried it out. If he had 100% confident certainty that it absolutely would have worked, he wouldn't have needed to run the experiment in the first place. It's also an experiment he's devoted his entire life towards, so we can possibly excuse him for getting a bit excited upon receiving definitive proof that his theory is accurate and that his device works.
      • And he didn't say "It works," he said "What did I tell you! 88 miles per hour!", implying that he did think it would work. It was the 1955 Doc who said "It works" when he saw the fully functional flux Capacitor.
  • 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.
    • After all, he might be a Commie.
    • There was a bit of a moral panic about wild, out-of-control teenage kids in the 1950s, and this is a teenage kid in a strange costume approaching them on an abandoned road. The couple assumed he was hopped up on something and panicked.
  • 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 DeLorean 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 DeLorean to power it, then gone back, say 30 minutes this time, and warned him properly?
    • The last trip is done with the car jury-rigged to power the time circuits from a lightning bolt. That must have required quite some tinkering, and it's very unlikely that Marty, knowing nothing of the inner workings of the machine, could undo the modifications and have it work from the plutonium reactor again. Presumably someone else might be able to do so, but how do you get a scientifically inclined person to look at a car-based fusion reactor that powers a friggin' time machine without them going "THE WORLD MUST KNOW ABOUT THIS" and spoiling the whole thing? And even if he did it - if, for instance, he held a team of scientists at gunpoint - who's to say that they can modify Doc's clearly non-standard work without ruining the rest of it? And then it sounds likely that the circuits themselves would be scrambled, after receiving such a blast from the lightning. And all that ignores a more basic issue - the car's engine is non-functional, meaning Marty can't drive it to 88mph. Even if he manages to hide it from where it's currently stuck before it attracts instant attention, fixing the engine or towing it to 88mph would at least require someone's help, and how is he going to explain all the weirdness on the car without generating excessive curiosity?
  • 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.
    • Wait.... when did Lorraine comment on Doc Brown?
      • Exactly, Lorraine disapproves of Marty's relationship with Jennifer but she never mentions Doc Brown ever.
  • How did the Libyans know that Doc Brown was at the mall in the first place?
    • "Oh my God, they found me. I don't know how, but they found me." There could be any number of ways. Doc Brown was in the phone book and his address was well known. Perhaps they went to his home first, and when he wasn't there they searched the place until they found a clue to Twin Pines Mall. Or they just drove around until they found his truck.
    • There's no evidence that they had one, but IF the Libyans had a Geiger Counter they would have been able to use it to find the plutonium. Even though it's shielded in a lead box, the time it spent out of the box when Doc's putting it in the reactor would have been enough to find it, and there's the actual use of it when he sends Einstein forward in time.
  • I wonder about the scene at the mall, When the van opens up and gives us our first spectacular look at the DeLorean, reversing it out if the van and opening those glorious doors skyward while Doc Brown steps out. While a great shot, since the DeLorean's doors are opening up, rather than out- how did Doc get inside the car? There wasn't enough room inside the van to accommodate for one of those doors opening up. Did he really get in the car while he was outside and drive it into the van, just to back it out just so he could unveil it to Marty?
    • Doc has a flair for the theatrical?
    • The gull wing doors of the DeLorean actually had more clearance than regular car doors (they were hinged very close to the centre of the roof) so it might have been possible for Doc to enter the car while it's in the truck.
  • I know it's Van Halen, but which is the song used by Darth Vader from planet Vulcan to fry George's brain?
    • Apparently it was just a random guitar solo that Eddie Van Halen specifically made for the movie.
  • I'm not a musician, but is "Okay guys, this is a blues riff in b, watch me for the changes and try and keep up okay?" enough information for the Starlighters to play a song they never heard before absolutely perfectly, sax riffs and everything?
    • Yes. Eight bar Blues (sometimes just called Blues) is extremely common, even for 1955. You'll find that there are many blues jams today where people just improvise over a known beat and style. The easiest method for someone is to use the "Blues scale" (a modified minor pentatonic scale) although there are many other ways to riff over basic 8 bar Blues.
  • In the original timeline, Dave (Marty's brother) is depicted as a loser, which would explain why he's working at some fast food joint and living with his parents, even though he appears to be in his mid-20s (the actor playing him was 27/28 when the movie was shot). But in the altered timeline at the movie's end, he's now a successful yuppie with a nice suit, yet he's still living at his parents' place. What's up with that?
    • Who said Dave has a permanent residence? He could just be visiting, or changing homes.
    • Or his job didn't require him to move from home, so he's taking advantage of the free room and board to save up more than if he'd had to rent an apartment.
    • There are plenty of people who still live with their parents unto their twenties. According to the card game, Dave is 22 at the time, so he probably just got out of college a few months prior.
  • What were the odds that the day that Doc invented time travel just happened to be the same day that Marty's parents met?
  • When Marty rides home from the town square at the beginning of the movie he comes in from the audiences' right to pull into Lyon Estates. However when Marty goes back to 1955 and he sees his future home, he is riding in from the same direction that in 1985, he came from the town square, but here he was coming the Twin Pines Ranch/future mall. The he continues forward, to the left of Lyon Estates and eventually arrives at the town square. So did he make a significant detour while riding home at the beginning?
  • As pointed out by the guys at CinemaSins, when Marty referred to Riverside Drive as John F. Kennedy Drive, why did his grandfather say, "Who the hell is John F. Kennedy?" as if you're supposed to know who streets are named after? Why not say, "Never heard of that street?"
    • Because typically, if a street has a full name and middle initial, it's named after someone extremely well-known.
  • When Marty and Lorraine were in the car at the dance, Lorraine was wearing a white jacket that she removed before Biff showed up. After George punches out Biff and he and Lorraine walk to the dance, the jacket was left behind in the car. However, when Marty says his goodbyes to George and Lorraine, George puts that jacket Lorraine had over her shoulders. (And yes, it is Lorraine's and not George's since George was holding his over his shoulder.) How did they get it? They didn't have during the dance and they couldn't have gone to get it after Marty finished playing the guitar since Part II shows that he walked off stage immediately after his "your kids are going to love it" comment.
    • Just a continuity error. All movies have them.
  • All right. The picture of the McFly siblings. Why did Dave and Linda disappear from head to toe, while Marty appeared to be disintegrating all at once? Also, Dave seemed to have taken like half the week to disappear, Linda most of the other half, and Marty took less than an hour?
    • This is mostly Rule of Plot Convenience stuff. The whole thing with the fading siblings in the photo doesn't make a lick of sense, but the movie is so well put-together that we, the audience, don't question the nonsensicality of it. Still, I'll try to explain it as best as I can. The reason why in the photo Dave & Linda disappear from head to toe is because that's simply the way it appears from Marty's perspective. From their perspective, they disintegrate gradually like Marty himself does throughout the series. As for the time discrepancies, I think it's because at first it was likely that George and Lorraine would still be together, explaining why it took so long for Dave to fade out, as he's the oldest sibling, with a job and such. As it becomes less likely for the two of them to be a couple, Linda and Marty's fading out speed rapidly increases, explaining the need for things in the first film to happen on a deadline. As for why they faded back into the picture so quickly at the Enchantment Under The Sea dance, I think it's because from that moment in time, Lorraine & George had fallen hopelessly in love with each other, and weren't about to leave each other anytime soon.
  • I can't believe I never noticed this before, but, why doesn't anyone call the cops or something on Biff after George prevents him from raping Lorraine? Yeah, it was the Fifties, but people back then weren't so unenlightened as to seriously think (attempted) rape is a-O.K. What gives?

     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 time-stream would also take a way bigger hit if they did that.
      • Not to mention that the Doc who went with Marty was one who was married to Edna for years and was torn up enough about ruining Young Emmett's and Edna's relationship that he turned against Marty to salvage it. There's no way he would approve of killing her.
  • 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.
      • The explanation is even more simple than that. 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.
      • Possibly Marty was worried about Emmett seeing him and derailing his plan.
  • 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.
      • The order of birth shouldn't matter since they traveled to a point when both Marty and Doc were alive. Plus Einstein had to have been born after Marty, given dog years, so why was he erased and not Marty?
  • 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.
      • No alternate Doc appears. Perhaps just the Delorean was duplicated.
  • 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!
    • Three words: Delayed Ripple Effect. Baring that, there's always this.
    • The reason the pictures changed in the movies was because the pictures were from the future, said future changing due to the alterations made. This particular picture was from the past, and the fact that that Doc was erased upon returning to 1986 doesn't change that fact that he was around in that timeline's 1931, since people still remember him.
  • 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.
    • Most likely Doc was afraid of causing more damage to the timeline and tried to avoid the number of time travel trips.
  • 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 DeLorean to no longer exist, cause a paradox? A universe-shattering one?
    • The Delorean seemed to last in the alternate timeline so theres wasn't much additional risk of paradoxes, especially since the sequels and games seem chockfull of paradoxes that haven't destroyed the universe. Plus Marty isn't known for thinking fourth-dimensionally, he probably didn't think of that possibility. Not to mention that Citizen Brown doesn't know as much about time travel and is focused solely on his own interests, so he might not have believed it or cared.
  • When does this take place in Doc's timeline? The DeLorean still exists, there's no time-train, and Clara, Jules, and Verne aren't even involved. The DeLorean does have the hover conversion and Mr. Fusion, but wouldn't Doc have gotten those when he heard that Marty McFly 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.
  • In the very first episode of the game, why was Marty SO incredibly stupid as to only go back in time a day before Doc was gunned down? If he had gone a week back or hell, to be on the safe side, a whole month, most of the messed-up timeline crap afterward could've been completely avoided!
    • Marty isn't very good at thinking fourth-dimensionally.
  • Why was the trip to 1885 undone in the Citizen Brown timeline. In the Biffhorrific timeline, Marty's initial trip to 1955 was maintained, as evidenced by Biff mentioning the manure truck incident and George having been an author, both of which occurred because of Marty's interference. This is despite the fact that it would have been impossible for 1985A Marty to travel back in time. The reason why it was maintained seems to be that the point of divergence of this timeline was November 12, 1955, while Marty had arrived on November 5. Nothing that old Biff could have done could change the fact that Marty had already been in 1955 for a week by the time old Biff arrived, unless he were to travel back to a date before November 5 and give young Biff the almanac then. So why is the 1885 trip undone if it took place before the Citizen Brown timeline's point of divergence in 1931?
  • Zemeckis and Gale described the timeline has only experiencing the effects of time travel after the trip to the past as taken place on a meta-time level. Therefore, in episode 5, when Marty gives Emmett the newspaper that inspired Emmett as Doc 55 years later to travel back to get Marty, he shouldn't experience the effects until 1986 of that timeline comes around and Doc travels back. So does that mean that in the timeline that episode 5 Doc came from, in which he had a good relationship with his father and returned to 1986, that there's a 72 year old "Michael Corleone/Harry Callaghan/Sonny Crocket" somewhere?

     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?
    • The Ride, if I recall correctly, takes place at some point after the future segment of the second movie. We saw that Doc had a device from that time period (or before) that could knock people out for a few hours; it's possible there's a similar device, at least by the time the events of The Ride take place, that produces some sort of controlled amnesia.
  • 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 efficiently 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?
    • Assuming the movies, The Ride and the Telltale game all co-exist in continuity, we now know that a duplicate DeLorean came into existence when the original was struck by lightning at the end of the second movie.

    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 themselves/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 DeLorean 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 occurred (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 only seen the Doc once 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 traveling 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 millionaire 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 meta-time 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.
      • After the timeline is restored and the main headline announces Doc being commended, the other headline on the page announces that Reagan is seeking a second term, so there's that.
      • That puts it in late 1983 or early 1984. Reagan had already been reelected by 1985 and I doubt Marty, Doc or Biff could have altered the timeline enough to effect when presidential elections are held.
    • 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, Alt 85 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 DeLorean 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...
    • A few other questions should be asked...
      • If Doc had been committed in the early '80s, why? If he'd asked Biff about the almanac, he'd have done worse than just have him committed (per Old Biff's instructions), and besides, Doc wouldn't have knowledge of the almanac anyway, because the trip that caused it began in 1985.
      • It's not stated that Doc was committed because of the almanac. Biff could have just had him committed because he thought he was crazy.
      • If he were released in, say, 1982 or 1983, could it be that most of the ground work had been laid for the time machine and that it was mainly a matter of finding a De Lorean and building it.
      • We know that in October of 1985, Marty was supposed to be in Switzerland, meaning the Marty of that timeline had probably been sent there the previous September if not earlier. How could he have been in Hill Valley and hob-knobbed with Doc?
      • Come to think of it, how did Marty and Doc meet at all? Oh wait, the RQ magazines in Marty's bedroom clearly demonstrate that he had a job at the library which is where they knew each-other from. However, this is unlikely in the Timeline of Biff.
      • There's no indication that Marty and Doc-A knew each other at all.

  • 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 completely reconstructed, so working with some unclaimed remains would be still plausible) With some rebuilds, the controls mostly automatized and Doc's Chemical Log you don't need many people to operate it, and hiding 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 disrupting the timeline: 1) He somehow manages to repair the flux capacitor 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 capacitor to work. 3) He uses the train to take him and Clara to 2015. 4) Using 2015 technology, he builds a new flux capacitor 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 capacitor 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 capacitor 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.
    • Given how the timeline hold together in certain ways, for example there's no repercussions for Marty and Doc effectively erasing their reasons to travel back to 1955 by burning the almanac, thus preventing 1985A, perhaps the timeline would have simply continued if Marty was erased, with him, from the perspective of the timeline, effectively briefly existing to ensure his own nonexistence.

  • "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 hand-waved as the time stream trying to keep George and Lorraine together, it just takes longer and longer 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, not an unreasonable assumption, given that Buford is known as "the fastest gun in the West" who killed at least 12 people, (not including Indians or Chinamen) and Marty's only experience with a gun is playing Wild Gunman at 7-Eleven. It seems to be a pretty fair assumption that the most likely outcome of a future where Marty faces Buford in a gun duel is one where Marty ends up dead.
      • 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. ;)
    • Because of the changes to the timeline, nothing in the future is set in stone until it happens. The picture shows the most likely future at the moment, regardless of whether or not there were time travel related causes. At the moment, it looked like the most likely future was one where George gave up and went home, thus Marty fading. However, when George changed his mind and went back, the most likely future was one where Marty and his siblings were born.

  • 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?
    • Doc covered this in his explanation to Marty. 2015 on the second film followed the improved timeline at the end of the first film. The alluded 1990s timeline where Lorraine killed Biff was the crapsack one that began in 1955 when 2015 Biff gave the almanac to his younger self. Just to go by Doc's explanation and without getting technical and academic, the two timelines were two separate lines that were totally unrelated to each other, except at the point where the second one skewed off. So Lorraine killing Biff in the 1990s didn't have any effect on the 2015 scenes of the film, where George Mc Fly was still very much alive and Biff was still an auto mechanic. Why did Old Biff collapse after emerging from the time machine? Notice Old Biff's pained but violently suppressed face while driving to 1955 Biff's home. So maybe Biff 'did have' a heart attack in 2015: driving or worse, time travel, was too much for him. As for the film makers' explanation, I think the twists of the plot were getting a bit too hard to follow, even if you were the film maker.
  • Another one on the picture of the Mc Fly siblings. Why did Dave and Linda disappear from head to toe, while Marty appeared to disintegrate all at once? Also, Dave seemed to have taken like half the week to disappear, Linda most of the other half, and Marty took less than an hour?
    • This has been already answered above.

    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."
      • Or perhaps he was named after a relative, who probably trumps a friend that you haven't seen in years in importance.
    • 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.
      • That raises another question: Why did George name his son after an indirect ancestor who died over half a century before George was even born?

  • 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 McFly (as seen in the old photograph in the library) all look like Marty, yet George looks nothing like any of them?
      • Recessive genes?
      • 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.
      • Not to mention the third movie showed that George's grandfather and great-grandfather also looked like Marty. Since he most likely knew William personally, given that William would only be 70 in 1955, he would more likely see Marty's resemblance to him rather than Calvin Klein.

  • 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!Lorraine 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.
      • Except that in the first movie, Biff clearly has a thing for Lorraine in the original timeline ("Say hi to your mom for me.").
      • Even if Biff doesn't want to get involved with her due to her supposed power taste, that doesn't stop him and continuing to make some passes at her. This is Biff after all.
    • Biff probably doesn't want to be married to Lorraine, he more than likely just wants to have sex with her. Honestly, I wouldn't put it past him to have an affair with Lorraine (or try to, anyway) just to humiliate George further.

  • 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 McFly 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.
      • Also, the fact that Marty drives the car around quite a bit in 1955 suggests that the Flux Capacitor and the rest of the car do not share the same power source.
  • 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 DeLorean can only travel in time, not in space, you know." He was just giving some quick examples.
      • In the novelization, 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 Mc Donald's 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 DeLorean 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 DeLorean 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 DeLorean 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.
      • This makes the most sense since the shifter for the DeLorean sits right in front of the switch for the time circuits. Marty accidentally bumps it when trying to drive away from the terrorists which is why he ends up in 1955.
    • Since "flux capacitor" is a mishmash 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.
      • This could also, maybe, explain why the time circuit readout only has four digits. You can't travel more than ten thousand years, so that the natural shifts of the earth's magnetic field don't shift you too far off course.
    • 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 light-speed. Exceeding light-speed 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 DeLorean (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 DeLorean as it accelerates? I'm thinking that those sparks have to be traveling somewhere between 87 and 88 miles per hour. When the DeLorean 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 traveling 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.
    • Mr. Fusion does not power the flight ability. The gasoline engine does. The flying circuits were destroyed when the car was struck by lightning.
  • Right. So I can believe that Doc went with a gas engine in 1988 because the nuclear reactor is carefully matched to the time circuits and it's impractical to power the motive capabilities of the car from plutonium as well. Fair enough. But why does this persist after he's had the car flight-converted and mr-fusioned? He now has a reactor that can effortlessly power everything in the whole damn car with a few banana peels, why the hell not make the drivetrain electric as well and get rid of a potential problem?
    • Because if he goes back to, say, 1985, he has to explain where he got a Fusion powered electric car. It'd become really obvious that the engine doesn't sound like a DeLorean gas engine should which leads to all sorts of uncomfortable questions.
    • A. Explain to whom? B. With all the stuff already implemented in the machine he couldn't add some "car sound" device?
      • Explain to any passerby or authority figure who happens his hear his car. Although I'm not sure if he would even take the Delorean out in public at all, given all the tech on it that's not usually on cars, plus the futuristic items.

  • Some Artistic License – Nuclear Physics here- the Mr. Fusion being powered by household waste. In Real Life, most fusion reactors fuse heavy isotopes of hydrogen into helium. Even the Sun is not capable of fusing together heavier elements at this stage in its projected lifespan, yet a small home appliance apparently can. But what really gets me is when the Doc puts in not only the half-finished contents of a drinks can and then the can itself. Question is, did alumin(i)um cans exist in 1985? (If it's a steel can, you can forget getting any fusion power from it, as iron is the one element that definitely requires more energy to initiate the fusion reaction than you get energy out from, making it utterly useless as a power source.)

    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.
    • The simple answer to why he's not in a sanitarium for the criminally insane is 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 Martys) or one of them was destroyed from existence (safe to assume it'd be 1985-A as it got there "latter").
      • Technically in the final timeline, the one that caused by Marty going back to 1885, there would be four Deleorans on November 12, 1955. The one that Doc put in the cave was in there for 70 years and when the 1955 of that timeline comes around, the other Deloreans would arrive a well. Look here for more information.
  • 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 realize 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!).
      • ^ This actually makes some sense, if you reflect back on the first time we saw the DeLorean - Marty watched it reverse out of the van at twin pines mall, and Doc Opened the doors upward for the first time and climbed out. But that means he would've had to climb into the car and drive it into the van in order to reverse it out - he couldn't open the car's doors while it was inside the van. The car did work via remote control also, so it would have made perfect sense for Doc to be standing next to Marty and use the RC to back it out of the van, rather than the effort it would take just to be inside the vehicle when we first see it... Sounds complicated, but it seems Doc Brown may have had a flair for presentation, and would go to extreme lengths just to make 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 (i.e. that the whole thing was just a bizarre dream), 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 McFly 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.
    • Doc will never accept this idea. If he somehow left 1885 the same day he arrived, he would have never met Clara. And even if the immunity to the ripple effect allows him to keep his Clara with him, he would still refuse: why rob an alternate version of himself (which is basically himself) the chance to meet his own Clara?

  • 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 wing-flap 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, for 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. He acted nice to Marty in 1985 since he lived with George and could easily tell him about Biff's jerky behavior. But since Marty Jr. wouldn't see George as often, there's more separation there.
      • 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.
      • Biff might just be better off in the long run anyway. In both timelines where he's in a "dominant" role his overindulgence has left him pudgy and losing his hair, but as an auto detailer he seems to be in much better shape and his hair is thicker.
      • Technically, he was losing his hair in the good timeline. You can see at the beginning of Part II that he has a combover. Perhaps his hair loss is related to genetics and not his place in life, so the changes in timeline don't affect 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 DeLorean, like the bumper cars have, connect the grid to the clock tower, and have Marty run for a time at 88MpH until lightning strikes and it's powers is channelled to the grid, and from the grid to the DeLorean. 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 DeLorean 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 dysfunctional 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!
      • Surely LP Doc had any kind of awareness of time travel, he'd in fact make a point of leaving plutonium out of the car in order to ensure that events followed the course they did once Marty travelled back in time the first time; to ensure that Marty would always be stranded in 1985, would always meet his parents, would always try to save Doc's life, etc.
  • 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 originally 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 befriend 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 avoids them, but this is because they look like fire. They could in fact be holes in the space-fabric left by the DeLorean. 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?
    • He would probably notice that his son bore an uncanny resemblance to his grandfather and great-grandfather before noticing the relationship to his wife's ex-boyfriend.
    • Obviously, George would assume that the same alien visited Roddenberry and Lucas.
      • His wife's ex-boyfriends tell them that they will have a children that at eight years old would burn their carpet. THEN they knew the truth!! But teenagers just need their space and live their lives.
    • 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 DeLorean 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 localized 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 traveling 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 McFlys weren't at home. They were out playing tennis. Biff himself is also a changed man: possibly he's even apologized 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 McFlys 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.
      • Maybe his car was at the shop and he was using his parents' car for the time being.
    • 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...
      • Personally, with the wig that made her look like Claudia Wells, there did appear to be some resemblance between Shue and Thompson.
  • Biff saw the flying DeLorean in 1955!!!
    • And the hover-board. 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 separate 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 DeLorean. He's looking up for exactly four seconds, during which time the POV shot shows us something unidentifiable as a DeLorean (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 disappeared and never was seen again. HOW is that Biff didn't committed 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 sci-fi/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 existence 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 hand-wave. 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 catastrophic 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.
    • Marty's line of "you look great, Doc" definitely has a bit of sarcasm in there, as if he's saying "yeah, dude, you look the same". The joke was definitely that Old!Doc looks almost identical to Young!Doc, despite Doc's concerns.
  • Why are we 5 years out from the events of the 2nd film and still without hover-board and flying cars? Seriously, Mattel needs to step it up.
    • We're getting there.
    • We destabilized 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, hover-boards, 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.
      • Or he could have just been making a joke about what one could do with a time machine and wasn't actually planning on watching the World Series, since he doesn't seem like that much of a sports fan.
  • 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 theorize 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 fan site that hypothesized 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 Valley? 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 understanding 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 Jennifer 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.
      • Doc's already been to 2015 once and has seen what happens to Marty and his family. His strict timetable might be to avoid running into his past self.
      • Some fanfics speculated that Doc could have meant to travel back to 10:30 at night rather than in the morning and he made a mistake with the time circuits. It would make sense given that he is usually discreet with time traveling. Perhaps his hurry could be him realizing his mistake and trying to leave before anyone saw the time machine (although that didn't work with Biff seeing it).
  • 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 traveling 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 misadventures 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?
    • It's probably for maintenance. If the mayor wants it gone, he likely cut public funds for keeping it from falling apart so they made up for it with donations
  • 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.
  • The note Marty wrote to Doc about the terrorist shooting. There's something that bugs me about it; I get that knowing too much about your future could be messing up the space time continuum, but...Marty wrote on the envelope that it shouldn't be opened until 1985, so I don't see what the big problem is. If he just preserved the envelope somewhere safe and patiently wait until 30 years later, there wouldn't be any problem reading it, as it would be informing about the near-present time. It's like if we have booked a meeting with someone; knowing that we are about to meet that person wouldn't mess with the space time continuum. There's no reason in tearing up the note completely; you just have to wait for the right time to read it. No big deal.
    • That's presumably what Doc ended up thinking at the end. Before that, though, he's fanatical about not doing anything to change the future any more than it already has been.
  • The segment where Marty is playing "Johnny B. Goode" for the teenagers of 1955. No, I'm not going to ask about the paradox, but rather with the issue of Marty's comment: "Maybe you guys aren't ready for that yet...but your kids are gonna love it." Sorry, but this tropette did some research, and the single came out just three years after that Enchantment Under the Sea Dance, and it that time the teenagers would be just 20 years old, meaning, still young people. It would make more sense if it came out about 10-20 years later to consider it more suitable for their children's tastes, but it's not much later from their own young years. My question is: why wouldn't the young people of '55 enjoy this song?
    • They were enjoying the music, it's just the last 30 seconds or so when Marty goes off into much more futuristic styles from the 70's and 80's that he lost the crowd, and the other band members.
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