Corrected entry: At the end of BTTF, Doc, Marty and Jennifer take off for the future. In BTTF2, they arrive 30 years later and see themselves. Impossible! They would have been inside the time machine (as far as those left behind are concerned) for 30 years. Marty and Jennifer were gone from 1985 to 2015 as far as he and everyone else knows. I can prove this by using the first movie. When Einstein goes into the future one minute, he was gone for a minute as far as Doc and Marty were concerned, even though the trip was instantaneous to Einstein.
Charles Austin Miller
27th Aug 2001
Back to the Future Part II (1989)
28th Feb 2005
Back to the Future Part II (1989)
Question: How does old Biff know how to operate the time machine?
Answer: Old-Biff first comments on the flying DeLorean "I have not seen one of those in 30 years", then he sees what he believes to be two McFly Jr.'s and gets even more suspicious, next he spies on Doc and Marty having an argument about the almanach and how Doc is opposed to time travelling for personal gain! What else does he need to know? And lastly: We're talking about a time machine here! Old-Biff could have stolen it, kept it for how ever long it took him to figure out how it works and returned it at leisure. We don't even have any proof for the days he picked to departed from 2015 or to arrive in 1955. The only verified date is his return from Nov 12 1955 06:38 pm.
Chosen answer: He doesn't, but it's hardly difficult to work out - the date setting readout is pretty obvious. Biff presumably set the date, then just accelerated the car until the time circuits kicked in.
Answer: It's a plot hole. Biff couldn't have known or suspected the DeLorean's time-travel procedure, which necessarily included Biff setting the precise 1955 destination with no previous instruction. Biff just suddenly "knew" how to operate a time machine. He also changed the timeline by going back to 1955, so there's no way he could have returned to the "normal" 2015. But he does.
It's not totally impossible that Biff knew how to the time dial worked. He wasn't suspecting what it was, he knew it was a time travel machine and thus knew what the dial was for and possibly being technically educated knew how to use the time dial.
We know from the first movie that Biff, by age 48, was waxing cars for a living in 1985. He hardly had a "technical education" and it's doubtful he acquired a technical education by age 78 in the year 2015. It was established in the first movie that he had become a timid underachiever.
Alright I agree, he's not the sharpest tool in the shed. But he has lived for 78 years by then, till 2015. Even though he has no clue on how the flux capacitor works, he doesn't need to, all he needs to do is work the time circuits, a simple keypad system which even shows which display shows which time. For someone from 2015, it's not so hard to figure out.
Answer: He could have taken however long he wanted to figure it out, as long as he returned it to the exact time he took it from. We don't actually see him time travel with it when he takes it, so, for all we know, he could have taken it to his house and taken the few hours/days he needed to figure out how to use it.
27th Aug 2001
Back to the Future Part II (1989)
Plot hole: If Old Biff changed his past and went back to 2015, he goes back to HIS future, not the bad future, but Doc later tells Marty that if he were to go to the future to stop Biff from taking the almanac, he'd go to the bad future, so Old Biff technically shouldn't have been able to return to "his" future at all.
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Suggested correction: The effects of the past being altered may not have happened immediately. It is possible that it took time for the timelines to adjust to the changes of events, meaning enough time would have passed to change 1985 when they return, but not enough time could have passed to change 2015. By the time Doc says if they went back to 2015 they would be going to an alternate future, some time has passed, so the effects of the past being altered and taking ahold in 2015 and altering it are more likely to have occurred by then.
Here is what you say: "perhaps it took time for the time lines to adjust." What kind of time would timelines take? Time is time, it doesn't take time to change the timeline. That doesn't make any sense. Some people claim it was the DeLorean itself that came back to its own original timeline and only then reset itself in the new one, but then the new timelines being erased later on wouldn't have happened either. So its a genuine plot hole.
It's established in the first film that it takes time for the changes to take effect. Marty and his siblings slowly disappear from the photo, rather than instantly. Although the scene in BTTF2 was deleted, it was filmed showing Biff dying and slowly fading away after his return to his present.
Yet they were restored instantly without any outside influence at the end of the movie. There are a lot of things wrong with this movie and the first one. Old Biff disappearing should mean that Marty and Doc should slowely disappear as well, even the DeLorean. But they didn't, that doesn't make any sense. The point is there is a plot hole, somewhere. To know where all you can do is look at it logically and then you automatically come up with Old Biff going back to the future but not the alternate future. If he did there wouldn't have been a movie, but that's the plot hole.
The timeline didn't change until he made his first bet which was some years I think after receiving it. He immediately travelled forward after giving the act, meaning he will still jump forward to the original future.
The timelines would instantly change, and Old Biff couldn't possibly have returned to "normal" 2015. It's just a poorly-thought-out time travel plot hole (or a deliberate error to expedite the storyline).
Suggested correction: In context, Doc was saying that they couldn't return to 2015 to stop Biff from stealing the time machine, because Biff didn't steal the time machine in the alternate 2015, he only stole it in the original 2015. Marty and Doc didn't stay long enough in 2015 after Biff returned, and that's why they didn't see any differences. Also, though they were unaware of it, Biff was dead in the alternate 2015, so the disasters he caused might have reverted back after his death.
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Correction: Wrong - the reason Einstein is completely gone for that minute is because he never goes back to the time he left. While Marty, etc. go 30 years into the future, they will eventually go back to 1985 and live the rest of their lives, therefore he can exist in the future.
The whole point and premise of BTTF is that Time is very surely linear, such that altering the past changes the future in such a way that time travellers can even erase themselves from existence. The BTTF story is not about alternate timelines, it's about the pitfalls of travelling in linear Time.
Charles Austin Miller
The way time travel works in the BTTF trilogy is that time jumps don't happen until we actually see them happen. Marty and Jennifer have not yet returned to 1985, so they obviously could not yet have lived out their lives to 2015. Also, the Marty we see in 2015 had his accident with the Rolls Royce, and when Marty finally does return to 1985 he avoids that accident, meaning that the Marty we see in 2015 can't possibly be from the timeline where Marty returned to 1985.
The original correction is correct. Everything happens simultaneously, for the time machine time doesn't matter whether it's the past of future. So the fact that Marty and Jen go back is important. Because going back makes it likes the travel to the future never happened. Because, and I want to make this absolutely clear, them returning means they travelled back in time again and that has more impact than only going to the future (which is what we are all doing all the time).
lionhead