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  • 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).
    • Simply put, the DeLorean was the first functioning time machine and if there was a limitation in how far forward or backward you could go, it was likely a software-based one rather than hardware (as in the time circuits, not the display unit). It could be remedied through a software change and switching from a digital to a computer-driven one later. Notably, computer displays of the 1980s were too bulky (CRT) and/or expensive (monochrome LCD) to fit into a cramped interior like the DeLorean's.
    • On the other hand, in a Back to the Future fanfic where Doc's kids go back 65-million years, one of his sons hooks up a special display to the time circuits to properly display that year only for Doc to later explain that it wasn't necessary, you just needed to enter the correct year, it simply wouldn't be properly displayed.
    • Maybe there really wasn't anything before 0000, and the birth of Christ is a thing that happened in this universe as Doc stated.
  • In the altered 1985 McFly household why does everybody freak out - notably Dave ("why wasn't I informed?!") - when Marty inaccurately notes that Biff 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?
    • 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 you were told that 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, it's unlikely 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.
    • 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.
    • A deleted scene shows it's Marty hooking it up though. 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.
      • 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?
      • An old 1950s set like that would actually be a lot easier to do that to than a modern one as the required 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. The 'RCA' signal format is essentially an electrical version of a a TV signal, so conversion isn't even needed. 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.
    • 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.
      • It's also possible that he simply took as a given that Doc's clocks would always be more accurate than his watch and therefore assumed (wrongly) that his watch was not working correctly when it appeared to be running 25 minutes fast.
  • 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.
    • 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.
    • Marty's had enough time-travel bullshit for one lifetime. He's not good at thinking fourth dimensionally, but he's almost certainly picked up enough to realise that if he travels far enough back in time, it can have calamitous consequences that he might not be prepared for and, frankly, that he doesn't want to deal with. He might not be able to do much damage if he goes back an hour before he left instead of ten minutes, but after the week he's had he almost certainly doesn't want to take that risk. So as far as he's concerned, eleven minutes is enough time to get back, drive from the town square to the mall, and warn Doc, so he puts in eleven minutes. It's not like he's planning for the car to break down, after all.
  • 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 it's the same gun and if it wasn't new to begin with that would explain why it breaks.
    • 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.
      • They may not have been aiming for his head, but there's still a chance they could have hit him there anyway, or his neck, or his arms and legs. Remember, Marty's note just said Doc would be "shot by terrorists". He didn't say where on the body Doc would be shot by terrorists. As such, Doc was taking an absurd gamble by trusting his life to a bullet proof vest, a vest that only covers roughly 30% of his body.
      • Worked though, guess he's still smarter.
    • 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.
      • Pretty much this. Had the Doc altered the scenario with the Lybians too much (by wearing more obvious armor or taking measures to neutralize the terrorists) he could end up damaging the integrity of the timeline. By wearing that vest he'd already be taking enough of a 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.
    • Fridge Brilliance. Lightning doesn't always strike downwards from clouds to ground, it can also go 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.
    • It doesn't need to be 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 a while, 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 rip the page? Because he had no pen available to take notes. 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, 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.
      • Compensation? For what Marty took that would be, what, a couple of cents at most? It's not like Marty has destroyed something of any real value here. It's not even the guy's own phone book, it's from a public telephone kiosk that happens to be in his diner. Phone book pages tear easily, were easily and frequently replaced, and that guy's job is to serve food and drinks, not maintain the phones. Unless he was a majorly obsessive pedant, the only reasonable response to seeing someone had torn a page out of a phone book would be mild curiosity or irritation at most. He's annoyed because Marty's wasting his time and not giving his business any money by ordering something, not because Marty's taken a page out of the phone book.
  • 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 inaccurate. 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. But, a lot of the people who are struck by lightning every year survive. 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.
      • Doc also isn't properly grounded if he's wearing common leather shoes that were available at the time, and voltage at its 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.
  • 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 BTTF2 and beginning of BTTF3.
    • Well, Doc can't be blamed for the existence of bolts of lighting, can he? He can simply say 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.
    • 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.
    • In the original screenplay, the present was 1980 but Marty still went back to 1955, not 1950 - i.e. only 25 years back. Doc's mention of seeing who wins the next 25 World Series is a remnant of that; at that point, the time travel was in increments of 25 years rather than 30. By the time the movie was made, that one line hadn't been changed, and by that time, 25 years in the future = 2010.
  • 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 keep 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.
      • People tend to forget what the past was really like. It's 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 comic series, there's a scene that takes place only days after the attempted rape where Lorraine reaches out to Biff to console him for the loss of his grandmother. This of course muddies the waters even further: she couldn't have forgotten that quickly what he'd done!
      • You don't have to forget to forgive, or even to forgive to be compassionate. Taking Biff's mourning as an opportunity to hurt him back for what he did might have been satisfying, but they were clearly trying to portray Lorraine as a better person than that.
      • IIRC Biff owns his own business, so George probably can't get him fired. He can, however, deny him business and spread word about why people shouldn't hire him, which amounts to something similar.
    • Values Dissonance. Attempted Rape (and even "successful" rape) wasn't as big a deal even in the 1980s (let alone the 1950s) as it is today. It's still wrong, and a crime, but the ability to report said crime and actually have justice done has expanded shitloads over just the last decade (and it's still incredibly difficult). George and Lorraine, of the 50's upbringing, just chalked it up to "youthful high spirits" and "drunken indiscretion" and didn't really poke at it any more than that. Plus, they had the balm of that "incident" directly leading to them falling madly in love and becoming happily married.
    • Biff's a local auto-detailer, and Hill Valley is a pretty small community. He might just be the nearest and cheapest option for them.
  • In the end of the movie after Doc survives being shot at, he hands Marty's warning note to him and explains that "Well I figured...what the hell?" Ok, so 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.
    • On rewatch 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.
      • As the universe is still intact at the end of the series, probably not. Marty probably took it off after the beeping incident and shoved it in his pocket, and just forgot about it when he was trying to prove himself to Doc. As other examples point out, he's not the perfect time traveler.
  • 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.
    • 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.
    • 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.
  • 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?
    • 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 since Marty shifts into 5th 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.
      • There's not 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).
    • Nature vs Nurture, if the Mcfly's children personalities are the product of their raising, then Marty's personality can't change as he was still raised by the parents of the original timeline and all his memories and experiences are still the same ones.
  • 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? The DeLorean stops and he sees the Libyans drive by and he tries to run after them. But if the DeLorean didn't stop and he made it in time to Doc before the Libyans came, what would he do cause we clearly see the other Marty is there with Doc?
    • He would have gone to the mall as fast as he could, and screamed "The Libyans are coming!" so that Doc and his former self would flee. Of course, this would create a paradox. But Marty isn't really thinking about that.

  • The whole plan in the first movie is based on the fact that they know the exact time when lightning will strike the clock. One problem with that: the clock is two-handed and therefore cannot show seconds. The lightning could strike at 10:04:05, or 10:04:17, or 10:04:58, but they act like it will definitely happen at 10:04:00.
    • Just because the clock doesn't have a second hand doesn't mean that someone couldn't figure out from the internal mechanisms when it stopped.
    • Which would make some sense since minute hands don't 'tick' like second hands, they rotate smoothly, placing them only on the numbers at precisely the second the minute begins, otherwise they sit somewhere between the numbers, one could in theory approximate, give or take a couple seconds, the time to the second when the clock stopped based on how far the minute hand had travelled past the number.
      • Except the clock tower clock clearly DOES 'tick' between minutes.
    • 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.
    • 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?
    • It's possible the person who wrote the article determined the exact time by examining where the clock's gears stopped.
    • The exact second doesn't matter. No car can be accurate enough to touch the cable at the exact second, and even if they knew the exact supposed second by the clock's third hand it could not be accurate (the clock could still move a couple of more seconds after the strike or be delayed, etc). The best they can do is hope that between the moment the lighting strikes and the moment the car touches the cable the electric current is still running through the cable, for which they have several seconds, maybe a whole minute. Thus they calculate that the car will touch the cable in the same minute the lighting strikes and hope for the best.
    • Lightning doesn't occur from nothing; it happens when differences in electrical charge between the ground and the clouds get so extreme that a massive discharge occurs to equalize the polarities. The bolt of lightning built up over time, and cut loose as soon as it was intense enough to be channeled through the best possible conductive path between ground and sky. In the original, pre-Delorean timeline, that pathway was provided by the clock tower on its own, and the bolt occurred at some point between 10:04:00 and 10:04:59 PM. In the timeline where Doc rigged up those wires, the instantaneous connection between clock tower, wires, and Delorean created a more favorable conduit than the tower would have on its own, and slightly changed history by attracting the lightning early.
    • The only way I can think of to get around this is to temporarily store the power in an array of capacitors to be discharged on contact with the wire, and after all Doc is an expert in capacitors since he built an entirely new kind of Capacitor that somehow enables time travel. This isn't even too difficult with today's techv the amount of energy stored in a capacitor is ½CV^2 where C is the charge and V is the voltage; in other words, quadruple the charge and you just quadruple the power, quadruple the voltage and you increase the energy sixteen-fold. Lightning is extremely high voltage so not very much capacitance is needed. the parasitic capacitance between the wire and the ground may be enough even.

  • How come Marty and Doc are okay with Doc bending the rules and wearing a bullet proof vest to avoid being killed, but Doc flat-out refuses to tell Marty about the accident that'll break his hand? On my first time watching 'Back To The Future Part 3', I fully expected Marty to call out Doc on being a hypocrite about this, but they never bring it up. Now, admittedly, the message is stronger knowing that Marty made the right choice knowing nothing about the situation, merely acting on impulse in the moment, but it does make me wonder why Marty just trusted in Doc's logic when, as said before, the guy was willing to bend the rules to save his own life, as well as being fine when Marty slightly altered his parent's lives, and eventually his own children's lives.
    • It's not just about Marty avoiding that accident specifically. It's about Marty learning and growing to become the person who would not have that accident.
    • In addition to the above about Doc wanting to prompt some Character Development in Marty, there's also the simple fact that if Doc hadn't worn the bulletproof vest, he would have died. While Marty knackering his hand and ending up a loser is unfortunate, it's not exactly life-threatening. Plus, there's also the fact that Doc only ended up being willing to bend the rules and wear the bulletproof vest because Marty kept insisting that he do it.
    • Doc's always been careful about giving away info about the future, it's Marty who isn't concerned about it. Who knows, maybe in the original timeline Marty broke his hand and later on found out Doc knew, giving him a big chewing out, but we never see it because it happened off-camera.

  • 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.
    • The novelization also specifies that the cost of the coffee was five cents. Nickels were made from the same material in 1955 as in 1985. So unless Lou looked at the date (and he clearly doesn't), there's no reason for him to be suspicious about it.
    • This scene did in fact happen in the first draft of the script, with Marty being thrown out of the cafe for trying to pay with 'counterfeit' money, at which point he saw George being hassled by Biff. It's possible they just put the two scenes together to save time, by having George hassled by Biff in the cafe that Marty was currently in.

  • 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 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.
    • Yeah, but if George hadn't turned the tables in just that way, he could indeed have had his arm broken if he tried to just worm his way out of the lock.

  • 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. Was it mentioned what his new day job was? Was it freelance writer, or did he write for the Hill Valley times or something?
    • 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.
    • Besides which, a novel can take some time to write. I've had ideas for novels bouncing around in my head for years that I haven't managed to complete yet. George probably had that particular idea stewing in his head for some time, but had only recently managed to get it into a form where he was happy with it being written and published as a novel.

  • 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?
      • The time is important because the mall parking lot is completely empty at 1 am. Doc needs a huge, wide-open and paved space to demonstrate the time machine.
      • 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 Marty to the past? Well, it would happen that the 1955 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!

  • 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.
    • It probably didn't take a lot of pretending. Bulletproof vests, even the souped-up one Doc was probably wearing, aren't exactly impact absorbent like Cap's shield. The vest keeps the bullet from going into you but you're still getting hit with a projectile moving at above the speed of sound and Doc got hit by a bunch of them. It probably knocked him out cold and he was only just coming around when he blinked and sat up.

  • Doc, don't you want to make absolutely, positively sure that time travel won't harm living creatures before you use your dog 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.
      • It's just concerning when Doc yells "IT WORKS!" all excitedly after the experiment. 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.
      • 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 that he only came up with earlier that day.
      • Remember also that Doc is from a generation of scientists that did things like shoot dogs, chimps and cats into space. Animal welfare was... not exactly a high concern at that time.
      • Yes, but... sentiments. Presumably even people from those times would be more hesitant to experiment with their pet than a random animal.

  • 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.
      • Also keep in mind a DeLorean looks wildly different from any car in the fifties. Mistaking it for a spaceship might be over the top, but thinking it's at least some sort of crazy government experiment seems probable.

  • 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, who's to say that they can modify Doc's clearly non-standard work without ruining the rest of it? Then consider it sounds likely that both the time circuits and the engine are malfunctioning. 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 1985 Lorraine of any timeline never mentions Doc Brown ever.
    • The award happened a while ago. The impression is that Doc, after hitting his head, slowly went mad (or so it seemed to people) over the next 30 years trying to invent the time machine.

  • 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.
    • Originally, I thought that they had tapped Doc's home/lab phone line since he told Marty exactly where and when to meet. However, if that were the case, they would've been there waiting and killed him on the spot. More likely, they knew that Marty was Doc's best friend and had someone following him. As soon as their lookout spotted Doc and Marty at the mall, he/she called the Libyans who hightailed it over to the mall. That would explain why they showed up when they did.
      • There's no indication that the Libyans knew who Marty was, let alone that he was friends with Doc. Them trying to shoot him was most likely just to leave no witnesses. Even if they did know, Marty only talked with Doc about the meeting on the phone and the part about it being at Twin Pines Mall was only said by Doc, so how would they know that Marty was going to meet with Doc?
      • Then they were simply watching his lab, noticed Marty going inside in the middle of the night to pick up Doc's video camera, followed him to the mall, spotted Doc and called in the shooters, who were on the other side of town and raced over.

  • 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 don't require as much horizontal clearance to open as it seems, so it might have been possible for Doc to enter the car while it's in the truck.
    • Or Doc modified the side of the van with an opening section to make ingress/egress easier.

  • 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. Twelve bar Blues, sometimes just called Blues (which "Johnny B Goode" is,) 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 twelve bar Blues. Any R&B band worth hiring would know how to play that progression.

  • 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 into 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?
    • David Hand's Improbability Principle. In short, you'd likely ask the same question if it was any other significant event in Marty's lifr: his parents getting married, him getting born, one or the other moving into Hill Valley...heck, you'd probably ask if any significant event in Marty's life happened on November 5th. So the odds for this specific combo is low, but the odds for anything we'd point as "unusual" is quite high.

  • 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. Then 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 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.

  • 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?
    • 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. Even if George and Lorraine had ended up together, say, during or after college, they themselves, and thus their relationship, would have been different. They may have still had kids, but those kids wouldn't be Dave, Linda, and Marty. Marty has to get them back together at the same time as they got together originally to preserve his own future. Marty may have been fading out due to being the youngest, or due to some kind of temporal isolation effect from traveling through time. As to why he starts fading away all at once, and right before the deadline is about to expire, is because after that moment during the dance, there's no way for Marty to still exist. 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.

  • 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?
    • People didn't "think it was a-O.K." George just figured getting decked and knocked out was punishment enough and nobody else saw it.

  • At the end of the first movie, Dave says that he "always wears a suit to the office". Does he also typically go to the office on Saturdays?
    • Maybe he had an extraordinary meeting on that day.
    • There are businesses and offices open on the weekends by necessity. Daily newspapers, for instance, or utilities companies.

  • Lorraine's puritanical attitude about Jennifer before Marty goes to 1955 is almost always pointed to as hypocrisy on her part vis a vis the way she acts with Marty in 1955. But could it be that she wasn't that way in the first 1955? Maybe pursuing Marty for that week made her realize it wasn't a bad thing for a girl to go after a boy she liked, even if she came to realize Marty was all wrong for her. That would explain why her attitude in the new 1985 is the opposite of the original one. (And that original attitude, although puritanical, would at least be consistent with her original beliefs.)
    • Lorraine tries to jump Marty's bones as soon as he wakes up, and it's strongly implied she has done things like this before. So meeting Marty certainly didn't change her in that regard, she was already like that. A much more likely explanation is that adult Lorraine simply is being hypocritical and/or has a selective memory when it comes to her own teen years. Such behavior is not that uncommon with parents of teenagers.
    • That is true...but if it's as simple as that, I don't see why she'd have a change of heart in the new 1985. Since she now loves Jennifer for the exact same reason why she disliked her before, Marty must have caused some sort of change. Here's my theory: in the original 1955, when it was George who got hit by the car, Lorraine fell in love with him but didn't have to pursue him. Given what a doormat George was and that he already had a crush on Lorraine (since he'd been spying on her), he probably fell into her arms at the first opportunity and that was that. With Marty, she had to make an effort, and that made her realize that wasn't such a bad thing to do for love. As for her claim that she had parked with boys before, 1) she could be lying to impress Marty, or 2) it could also be that she saw a difference between fooling around with boys who had asked her out, and actually being the one to pursue the boy in the first place. You do see that all the time with teenagers (i.e. they can still claim to be a virgin if they've only had oral sex, etc.), and it probably happened in 1955 too.
    • It's very common in real life that parents nag their children for doing stuffs they denied they did at the same age but that they indeed did, that and the fact that Lorraine probably wasn’t virgin (or at the very least had very hot make-up sessions) when she marries as is implied by the “park before” implicit in the look that Mary gives is more or less the joke. If we could time travel we’ll find out that sort of things of our parents. However, the reason why she had a change on her attitude toward Jennifer is probably more psychological. To me, in the original timeline she whether subconsciously felt jealous about Jennifer as she saw herself at her age with all the potential and happiness than were later wasted, or she, also subconsciously, doesn’t want her to make the same mistake she did even if that means marrying her son.
    • Being that Biff was pursuing her so aggressively, and attempted to rape her in the new timeline, it's very possible that he made an attempt (perhaps a successful one) at some point in the original timeline. Being that Biff was obviously never punished for his attempt in either timeline, it's very likely that Lorraine would have come to believe that it was her fault for the way she dressed and acted around boys. Her advice to Linda would have come from fear that, if Linda followed her mom's actual example, she would wind up getting raped and would wind up believing it was her fault... which is actually not that much more unreasonable a conclusion in 1985 than in 1955. The horrifying part is that it's very likely that Lorraine pushed herself to pursue other guys - and wind up marrying George as soon as she realized that he was both interested and willing to seal the deal - as an attempt to protect herself from Biff.

  • $300 (the cost of Biff's car repair after the manure incident) in 1955 dollars is almost $2,700 in 2016 dollars. It's extremely unlikely Biff would have had that much money, and if he did, he could have bought a decent replacement used car for less.
    • Perhaps young Biff did have that much money. He lived with his grandmother, and yet seemed to have no economic problems and in fact was a high school kid who owned a car in 1955. We know from the alternate 1985 Biff that he has zero qualms about commiting crimes for personal gain, so who knows what kind of illicit business he ran along with his three friends.

  • Marty tries to order a Pepsi Free in 1955, but in his time Pepsi Free was only recently introduced. Tab was introduced earlier in 1963, before Marty was born, so it makes sense that he wouldn’t know Tab didn’t exist in 1955, but Pepsi Free was introduced in 1982, when Marty would’ve been 14, so surely Marty would know Pepsi Free didn’t exist in 1955.
    • People who are freaked out and disoriented, which Marty is especially considering he's thirty years in the past, don't remember semi-obscure soda trivia they probably weren't paying attention to when it happened in the first place. Marty's on autopilot at best at that point. He walks into a diner, he orders what he always orders.
    • The guy's travelled thirty years back in time, he's disorientated and asks for his usual order without thinking. Cut him some slack.
    • Besides which, do you remember what soft drinks were only released when you were a pubescent? Were you even remotely paying attention to the branding initiatives of Pespi-Cola when you were fourteen, beyond maybe thinking of buying one if you happened to stumble across an advert and were thirsty? Because it's almost a guarantee that Marty wasn't.

  • About George. Wouldn't his son growing up to be the spitting image of his wife's high school crush be enough to make him certain he's been cheated on? She even named him after the guy's nickname!
    • Marty wouldn't be born for some 13 years after 'Calvin' completely disappeared from their lives. Plus they only knew the guy for a week. It's unlikely that either of them remember exactly what he looked like by the time Marty grows into a teenager.
      • Plus the third movie reveals that George's ancestors looked like Marty, so he will more likely think that Marty is the spitting image of them. On top of that, Marty is the youngest of the kids, so unless 'Calvin' somehow reconnected with and slept with Lorraine thirteen years after she and George got together - despite her discovering her lack of attraction to him in 1955 - it'd be impossible.

  • When Marty returns to 1985 at the end of BTTF and finds out that his entire family is different... where the hell is 1985' Marty? BTTF2 and the Telltale games establish that each version of 1985 has a Marty that is doing stuff (run out of town, run out of town again, camping, what have you), but won't they eventually return? And if they somehow vanish when original Marty appears, he isn't getting the new memories of those timelines, so even when he finally gets back to 1985, his life could potentially be very different, and he wouldn't know what he should.
    • At the end of BTTF, Marty returns to see the "new" Marty leave in the time machine as Doc is shot at by the Libyans. Where that Marty went at that point is subject to Wild Mass Guessing.
      • Possible Fridge Horror: That Marty went back to the same week, but was a Marty of an alternate timeline, henceforth events played out differently and (assuming this new Marty made it back at all) he too would be coming back to an entirely alternate timeline from Marty-A.
      • Way back before the second film came out, Starlog magazine published an article that explained what might have happened to the Marty we see departing at the end. Because he owns the truck, he's a better driver than 'our' Marty so he doesn't lose control of the DeLorean and avoids crashing into the barn. The Doc he's left behind knows what is going to happen to him in the past so has stored an extra charge of plutonium in the car. Marty simply loads it up and returns to 1985. Thus he never interacts with his parents and history unfolds as it did first time round. Which means when he gets back to his own time he finds that Doc is dead (because he never met Marty in 1955 so never got the warning note) and his parents are losers (because George was never inspired to stand up to Biff).
    • This one is simple: The 1985's Marty you ask for, just went to 1955, and lived through everything the other Marty did. It's a Stable Time Loop of Marty giving confidence to George, and George raising Marty as a determined man. The Marty who we see in Back to the Future Part I is the one who started the Loop.
      • Adding to that, when time must catch up to itself, it establishes changes based on the current timeline. When Marty returned he saw that he still existed, meaning it would only be a matter of time before Marty would completely forget about his old familial life and instead be replaced with the memories of his current one. The way this works is similar to the slow fade-out of Marty's hand, except where that was erasing him from existence in this case it's simply reassembling Marty's identity, which is EXACTLY why in the following films his personality changes to reflect his new upbringing (i.e. his need to defend his honor when someone calls him chicken because he now grew up with a confident, assertive father figure).
      • Doc appears in the second movie to recognize that this happens, because he insisted on going back to 1955 to fix the corrupted timeline immediately, even though the time circuits on the DeLorean were acting up.
      • Shown when Jennifer shows up in BTTF Part II. Yes, she was played by another actress, but she could have had different DNA but Marty would only recognizer her as Jennifer, not "why do you look different" Jennifer.
    • What the "new" Marty that the "original" Marty inadvertently created would experience when going back to 1955 does raise some questions. It can't be exactly like the "original" Marty's experience. Presumably he would push young George out of the way of the car, preventing his parents from falling in love, just as original Marty did. But he wouldn't think he was changing the way his parents met, because he grew up in the altered timeline where George never got hit by the car. It raises the question of what the George and Lorraine of the altered timeline told their kids regarding how they fell in love. Did they mention that Lorraine briefly fell for a mysterious young man who seemed to come out of nowhere and then never was heard from again, before George succeeded in winning her heart? If so, this Marty might put two and two together and realize he was the young man they spoke about—in which case his experience would look a lot like You Already Changed the Past. And that would affect the whole way he and Doc come to view time travel, because it would make the past seem much less malleable to them. In that case, you wonder why he or Doc would even bother to try to meddle with time like they do in the sequels, creating even further paradoxes... Ok, I have to stop, my head's starting to hurt.
    • It works like the YOU'RE FIRED fax, only Marty is the fax paper. He'd exist, and come to exist in his time, place, and position that he always did, as long as George and Lorraine got together, but what's "printed" on him could only change after some time had elapsed. He goes back a little while after Lorraine realized she'd be with George for the rest of her life, so the changes didn't catch up with him until after he'd gone back to 1985. New Marty IS Old Marty, just with new memories. The Marty that goes back to 1955 at the end of the movie whose memories have, presumably, never been changed and match the new ones, will just do the same things he always did, for a different reason (he might not know why Lorraine is attracted to him after he gets hit by a car, but he'd definitely want to save his father's life from getting run over). Or, since Doc knows how 4th-dimensional correspondence works, he could have hidden a letter for Marty in the DeLorean explaining it all.

  • When in 1955, Marty had a picture of him and his siblings with him. Why couldn't he just claim to Lorraine that the woman in the picture was his girlfriend? With "Calvin" already "taken", it could have caused her to move on.
    • His sister was wearing a sweatshirt that said "Class of 1984". Showing Lorraine a picture of a sweatshirt with a date nearly 30 years in the future would raised a lot of questions. More importantly his brother's head had already faded from the photo by the time Marty realized what was going on. That would have freaked Lorraine out and Marty couldn't conceivably answer those questions without revealing that he's Lorraine's son from the future, which would be a bad idea.

  • Then again, why didn’t Marty tell Lorraine about Jennifer? Lorraine would know Marty had a girlfriend, which would be a good reason for her to give up on him.
    • Once Marty realized his existence was in danger, he was mostly focused on getting George to ask her out and didn't really interact with Lorraine until she asked him to the dance, which he went along with when he came up with a new plan.

  • Marty being in Lorraine's room: It makes no sense that the Baines family would put Marty in the same room with their same-age daughter considering 1955 society and moral standards, especially considering the Baines family had several sons. Lorraine's parents would have put Marty in a room with the boys, not with Lorraine.
    • Teenage Lorraine is shown to be both something of a fast-talker and good at playing the innocent, sweet girl in front of her parents. Besides, she had clearly been the one to volunteer to take care of him while he was knocked out, so she would have been alone with him whether she was in her own room or her brother's.
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    Paradoxes 

  • 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.

    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.
      • The picture starts to fade as soon as Marty prevents the initial meeting between his parents, showing that it is getting increasingly unlikely for George and Lorraine to end up together. At the critical moment (does George kiss her during the dance, cementing him as the man she's destined to spend the rest of her life with) approaches, the fading increases, because Marty has no reason to exist if it doesn't happen. That kiss is the deadline the fading photograph is building up to. Marty has to get them together by that moment to preserve his future. Even if George and Lorraine meet and fall in love later, say during or after college, they'll be different people, their relationship will be different, and their kids will be different (if they even have kids).

  • 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.
    • It seems likely that the last-second "cut-in" was actually a result of Marty's changes. In standing up to Biff, George established himself as someone not to be messed with, and so some other idiot will want to mess with him. In the original timeline, no one thought it was "worth" trying to grab George McFly's girl at the dance, because. . . well, she's with George McFly After Marty sets in motion the chain of events leading to George decking Biff, now someone wants to make a name for himself by standing up to the guy who stood up to Biff Tannen. Marty is fading because the critical moment that ensures his future (George kissing Lorraine at the dance) hasn't happened yet, and the decision is still up to George, whether the newfound confidence and assertiveness Marty helped him to discover will remain, or whether he'll revert to his lifetime of meek passivity. Until George himself makes that choice, Marty keeps fading.

  • Another one on the picture of the McFly 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?
      • Because it's a nice name. Because Martin McFly was the original McFly to settle in American and George felt like honoring him. Because it's a family tradition in some way. Any number of possible reasons, really.
      • Technically it was Martin and Seamus who were the first, but then again maybe thats why they had Seamus as the middle name to go with Martin.

  • 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 Seamus, Marty Jr., Marty's daughter and William McFly (as seen in the old photograph in the library) all look like Marty, yet George, Dave, and Linda look nothing like any of them?
      • Recessive/dormant 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.
      • Maybe Arthur McFly took more after his mother (let's call her Miss Jones) than his father William McFly. George takes after his father and looks more like a Jones than a McFly. Dave and Linda take after their father, still with the Jones look. Yet the "recessive" McFly genes reappear with Marty.

  • 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.
      • In addition, while Marty may have spent a week trapped in the past, it seems like he's only spent a few hours with George or Lorraine.
      • Eidectic memory (more appropriate here than Photographic Memory) is described as "typically found only in young children and are virtually nonexistent in adults".So, without an actual photograph of Marty hanging around, literally no one is going to remember the exact appearance of someone they only briefly met thirty years prior.
      • 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 poor taste, that doesn't stop him from 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).

  • Do Marty's parents even know he and Doc Brown are friends? There are a few close calls here and there (notably at the end of the first movie/beginning of the second), but they never see the two of them together that we're aware of. The only adult who makes any mention of their being friends is Principal Strickland.
    • Most likely yes. Word of God says that Marty has been friends with the Doc for 3-4 years by the events of the film, and he actually had a part-time job as the Doc's lab assistant. Unless George and Lorraine are REALLY that neglectful towards their children, they had to know.

    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.
      • Which is common knowledge now that electric car engines are slightly more common than "nonexistent" but not so much in the eighties.
      • 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.
      • The Flux Capacitor requires a huge amount of power to work. That doesn't mean just driving the car around requires that same amount of power. Maybe the batteries were only at 5% charge, far too little to time travel but more than enough to drive around for hours (which would mean that Doc made an electric car that's better and more efficient than the majority of the ones we've got but then he is Doc Brown).
      • Marty never drives the car around "a lot" in 1955. The first movie has it die shortly after he arrives and from then on it's either being towed or pushed around, the next time it actually drives is during the lightning sequence when it could be implied they'd rigged up some method to charge it just before hand. The second time they're in 1955 they hide it and don't bring it out until they go chasing after Biff, which features it mostly flying.
      • We also hear the engine starting several times, as well as the repeated cranking when Marty was prepping to return to 1985. If an electric motor starts making that noise, get a fire extinguisher, pronto.
  • 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.
      • The commentary said 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!
      • 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.
    • Worth noting that the signing of the Declaration of Independence was on July 2, 1776, so they'd miss that too, if they used the date entered.
    • That's exactly why they chose those two dates: an inside joke representing legendary historical events that didn't happen exactly when most people think they did. Also, in the novelization, Doc does mention you'd still have to find a way to get to Philadelphia or Bethlehem to see them (and also mentions the dispute over when Christ really was born).
  • 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 McDonald'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.

  • So this is a long one, but I've thought about it for years... in the epic and memorable finale to the first movie, the Delorean is tearing down the street towards the wire. But is there any reason (outside of time and available parts) why Marty and the Doc couldn't just build a rudimentary conveyor belt system, mount the Delorean on it, with cable running from the clock tower and directly into the Delorean's machinery? That way there'd be no concern about driving it up to speed, they could've just had it where it was the entire time and maintained the speed of 88pmh until the lightning hit. Hell, Marty could've even helped Doc fix the cable when it inevitably fell
    • Furthermore, couldn't they have done the same in Part 3? With the engine dead, and train wheels as an option available to them, couldn't they have built a basic steam engine, attached it to the wheels, put the Delorean up on bricks, and then simply cranked up the heat with the Presto Logs we see in the finale, to make the car's wheels spin up to 88mph? The only conclusion I can come to is that the car has to actually be MOVING, as opposed to the wheels just turning, since according to the finale, Marty and the Doc pushed the car towards a lethal cliff-edge in order to travel
      • The car has to be moving 88 MPH. Not just its wheels spinning at 88 MPH.

  • 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 1985 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.)
    • Yes, we hoary old men over 35 can attest that aluminum cans existed in the US in 1985, and had been the predominant disposable drink container for quite a few years at that point.
    • In fact, it's been used for drinking cans since 1959. Young people these days...

    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.
      • Zoning rules and regulations from 1985 are completely different from 1955. A lot of the modern zoning rules didn't even exist until the mid 70s.
  • 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 '50s. 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.
  • 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 as well. Look here for more information.
  • 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.
    • 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 only about a half an hour. 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.
    • Also, look at George and Lorraine's faces right after Marty says "if you two ever have kids." They're very embarrassed that he'd even bring it up, since having kids requires. . . well. . . something you don't really talk about in the 50s. So they probably intentionally forgot about that little bit of conversation to save themselves and each other further embarrassment, until/unless some years later one of their kids actually does accidentally set fire to the living room rug. Which may not have happened after Marty's messing with time, or may have made them really wonder about who this "Calvin Klein" person actually was.
    • It is, of course, strongly implied that both George and Lorraine are much better parents after Marty gets done with them in 1955. Whatever turn of events led to Marty setting fire to the couch in the original 1976 (maybe Lorraine didn't notice him playing with matches because she was drunk?) might well have been averted in the subsequent one.
  • 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?

  • 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.

  • 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?
    • Maybe you just push and pull on the steering wheel the same you do on a plane's yoke.

  • 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.
      • I mean, there were hippies who were terrorists, so I guess the inverse would make as much sense.

  • 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.
    • The answer to this one is a lot simpler than people make it out to be. While the future that TP Marty ends up in is different, the past that LP Marty arrives in is the exact same past that TP Marty arrived at the beginning of the movie; he arrives in the same place, at the same time, still crushes the second pine tree, still walks into town, still bumps into Biff and his father at the diner, and so on. LP Marty will go on to do almost the exact same things that TP Marty did, with only some minor differences (such as, he will be astonished to discover that his cool and confident dad in the past was actually a clueless dork, and so on), and will return back to the same LP timeline having accomplished what the original TP Marty did, with the only difference being that instead of creating that timeline as TP Marty did, LP Marty is simply ensuring that timeline. Essentially, while TP Marty created this new timeline, LP Marty's travel back in time becomes a Stable Time Loop that ensures it remains the actual timeline. As for TP Marty, just as the photograph of his siblings changed to fit into a potential new timeline, so his memories will gradually change to adjust to the new LP timeline that he as created.

  • 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.
    • 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.
    • The comic book series features an origin story. The Readers' Digest version: in 1982, Needles broke the vacuum tube from Marty's guitar amplifier, and Marty went looking for a new one, only to find the music store had just sold their entire stock to Doc, whom he knew by reputation only at the time. Doc had a series of puzzles that allowed access to his lab for anyone who could solve them, and Marty was the first one who could, so he offered him a job. As for the tubes, he just needed the box they came in because it was the right size for one of his experiments.
  • 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.
    • Going back to the original question, Marty writes "not to open until 1985" because Doc is adamant about not knowing about the future, Marty probably thought that the only way he might accept to read the letter if is it stops being about the future i.e. is a letter that you should open only in the exact year the event it warns is going to happen (and yes, if he opens the letter in January 1, 1985 it will still be about the future but he probably thought that it was the safest bet to allow Doc to have some time to analyze the content of the letter and not just put the exact date of the event, and of course the definition of "future" is complex, as the movie works with years the same entire year could be "present" in Marty's mind). In fact, Doc himself when taking the letter nor even reads the content, he just says "Is about the future, isn’t it?" and tears it. Marty’s plan could indeed work out has Doc read the envelope (and/or maybe it did, considering that Doc did read it). As for the bulletproof vest, Doc doesn’t knows exactly what happen, Marty only tells him he will be shot, so he probably uplifts with Science! an ordinary vest to protect himself from every conceivable weapon that fires bullets.
  • 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 resemblance 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...
      • To run two miles in ten minutes, you'd be running at 12mph. A quick Google says the average human running speed is 10-15mph, so what Marty does isn't implausible at all, especially for a young man in good shape and, as mentioned below, a big motivation to keep his adrenaline flowing.
      • 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"?
    • Giga with a soft g is preferred by scientists. For instance, the NIST gives that as the only correct pronunciation, and they even praise the movie for getting this detail right.
    • 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.
      • Marty is seen throughout the film to be highly impulsive, and to make foolish decisions without thinking through the consequences. Furthermore, he's under extreme pressure at that moment, with very little time to think about what he's doing anyway. It's actually a terrible idea for him to try to arrive earlier, for the very reasons we see: there end up being two Martys, and he places himself in real danger of creating another paradox. But that's something Marty repeatedly shows difficulty understanding. He probably reasoned that the closer he was to the point his earlier self went back, the better, and that if he goes back too far he'll simply have to wait around. But, again, the "plan" was not well thought out because he came up with it on the fly basically out of desperation.
    • 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 '50s 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.

  • 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).

  • 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.
      • The "some sort of liquid" was probably water, which is actually an extremely effective radiation shield. Since the rods seemed fairly small, that amount of water was probably all that was necessary to reduce their radiation to a level they could be safely handled for brief periods outside of their shielded container.

  • 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.
    • You could also argue that they're not the same individuals. Dave clearly has his act together far better after The Punch than before. We don't see enough about Linda to know how she's changed, but she undoubtedly has changed in some way just like the rest of the family. The only way in which they definitely haven't changed is in their looks. Since they still have the same parents, that much makes perfect sense. As for their ages being the same, remember it's not so much a matter of when people have sex as it is of whether the woman is ovulating when they do. Marty changed a number of things about his mother, but her cycles probably weren't one of them.
      • "Since they still have the same parents, that much makes perfect sense." No. Siblings have the same parents as each other, but the only way they can look exactly alike is for them to be identical twins, ie. to have come from a single sperm, that fertilized a single egg, which then split into two parts. In order for Marty and his siblings to look the same, they each would have had to come from the same individual sperm meeting the same egg, which is, as OP says, astronomically improbable even if George and Lorraine still had sex in the exact same way at the exact same time, and can only be chalked up to time itself intervening to prevent major changes to the timeline.
      • Why wouldn’t they have Dat the same time? Marty’s intervention only took a week, they probably dated for months if not years, married in the same date that the original timeline and had sex in the same wedding night assuming they waited which was customary in the 50s and as all their children seem have born several years after they married whether Lorraine was using contraceptives if they had premarital sex (which wasn’t uncommon in the 50s either) or they did wait until they got marry, in any case if the marriage was in the exact same date than the original timeline a week of difference in the date they start dating is not going to change much of the rest.
      • Look, at some point we really have to remember that it's just a movie and relax. Yes, the chances of Marty and his siblings turning out any way the same whatsoever, never mind pretty-much-the-same-but-with-improved-personalities, are impossibly astronomical after Marty's meddling. But you also have to remember that this is the end of the film, most of the watching audience aren't pedantic nerds like the denizens of TV Tropes, and they just want to know that the story they've been enjoying has been wrapped up and that everything worked out (or didn't) for the characters. Marty and his siblings being wiped from history and replaced by different people who were the product of different sperm fertilising different ova at different times due to their parents having sex which produced children at different times might be a more accurate ending from a scientific and probability perspective, but most of the audience would likely hate it, and even the hardcore science nerds and pedants in the audience would probably find it pretty unsatisfying. And the reason for that is because what it's doing is essentially wiping away the characters they've spent the last ninety-odd minutes following and getting to know and like and replacing them with completely different people the audience hasn't had a chance to get to know. It creates an unnecessary Downer Ending or even a confusing Gainax Ending which requires too much explaining for people to follow and which renders the entire rest of the movie utterly pointless, for no other reason than to pedantically acknowledge a scientific point related to a field of science and technology that hasn't even been definitively discovered yet. The movie ends with Marty and his siblings more or less the same people but with slightly different personalities because that's better for the story, science and probability be damned. If there's anyone who can't accept that, then this movie simply isn't for them, end of story.

  • 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.
      • Nah, it works, so it had a 100% chance of working. That's just basic logic.
  • 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.
    • 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 BttF 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.

  • 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).

  • 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
    • Donations probably help pay for things like the flyers, for signs if they do protests, materials and gas if they go around asking for signatures on petitions, potentially lawyers to sue the city to have the clock tower designated a historical landmark, or more cynically to pay the head of the Save The Clock Tower foundation a salary that they don't really deserve.
  • 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. 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.
    • Time travel doesn't work that way. Knowing something about the future "sets in in stone", so to speak, and it doesn't matter if the event takes place 30 years or 30 seconds later - it's something that now must happen. There's a difference between planning to meet someone (if you don't make it you reschedule) and having to meet someone because causality says so (if you don't make it you create a paradox and the universe implodes).
    • Watch the scene carefully; Doc nor even reads the envelope, he says "Is about the future, isn't it?" without even looking at it. So yes, what you think is correct and that was Marty's reasoning, and it probably was Doc's reasoning once out of curiosity he saw the teared paper strings and probably saw "85" in one on them or something like that.
    • Tying into Fridge Brilliance, Doc may have remembered what Marty said about George standing up to Biff, and looked at the photograph, realising that it was still there and come to the conclusion that there was no harm in little changes now and then, hence him taping the letter back together
  • 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?
    • The audience actually enjoys the rendition of "Johnny B. Goode" hugely, it's just the last 30 seconds or so when Marty plays his great big, Van Halen-esque guitar solo that he lost the crowd, and the other band members.
    • Chuck Berry's first hit, "Maybellene," hit the top ten in August 1955, about three months before the Enchantment Under the Sea dance. Odds are at any real-life high school dance that fall, several of the kids in attendance owned a copy.
    • Also, Marty is not an expert about the past, he has no way to know the data you do know. He probably just thought they didn't were ready for that kind of music (when in fact it was his heavy metal antics what pulls them off), Marty is an high school age teenager, is normal he would make mistakes like that.
  • I've always been bothered by the business with the letter. Doc should have been able to figure out most of what the letter told him, before he even read it. He watched the entire videotape. He knew his older self had intended to be the one who traveled in time, but that for some reason it was Marty who got sent back. He knew the videotape ended with older Doc saying "Oh my God. They've found me—I don't know how, but they've found me... RUN FOR IT, MARTY!!!"—which is extremely ominous. And he was seen repeatedly watching that point, so he was clearly wondering about it. Furthermore, he saw how frantic Marty was to tell him something about the night he went back, and Marty even says outright "Your life depends on it!" He didn't need to be a genius (even though he was) to piece all these clues together and realize (or at least entertain the possibility) that he was going to die that night. It seems glaringly obvious based on the clues he was given, even before he looked at the letter. The only new piece of information the letter would have given him was that it was terrorists who shot him—which was ultimately crucial to his preventing it, but it doesn't explain why he was so adamant on not listening to Marty for so long.
    • Doc Brown is established throughout the franchise as not being terribly bright and having a tough time figuring things out, that's probably why.
    • Probably willful ignorance on his part.

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