139

According to co-writer/producer Bob Gale: We never explained it in the movie. But the history of the characters that Bob Zemeckis and I created is this: For years, Marty was told that Doc Brown was dangerous, a crackpot, a lunatic. So, being a red-blooded American teenage boy, age 13 or 14, he decided to find out just why this guy was so dangerous....


41

I think that, in the beginning of the film, Doc really doesn't have the letter. Marty's actions in the past changed our present, which is visible by the changes in the characters of Marty's family members and Biff, by the "pines" sign, etc. (image source) There is no reason for the letter to be an exception.


37

The Doc Brown in 1955 is younger than the Doc Brown in 1885, by 30 years. The Doc Brown in 1955 will still live for another 30 years before traveling back to 1885 and being shot by Buford.


35

You do have a point in that the fuel could have been syphoned. However, it's more likely that there just wasn't any. When the doc gets back to 1885 with broken time circuits, he first tries to fix it. When he realizes it can't be fixed, he buries the car in the mine after first draining it of all fluids. While it is unclear if the car could be dug up, it ...


28

Yes. This is discussed by the creator of Rick and Morty in the Back To The Future documentary that was released recently. See the Wikipedia article on Rick And Morty. The series has its origins in an animated parody of Back to the Future created by Roiland for film festival Channel 101.


28

Bleeding Cool addresses this: In the Blu Ray commentary for Back To the Future, producer Bob Gale says: The opening shot, when the camera is going through Doc’s laboratory, there’s a newspaper on the wall that says the Brown mansion was destroyed in a fire. You can infer from that that maybe Doc set his house on fire to collect the insurance ...


26

What makes you think the lightning could strike before the clock tower was grounded (by Doc plugging the cables back together, the metal poles beside the road providing a path to ground). Things to note: When the plug near the ground pops loose, the free end is stuck in a tree, not too close to the ground, so not a great path to ground. Lightning is ...


25

The car had to reach a velocity of 88 miles per hour. It had nothing to do with the speedometer hitting 88 miles per hour. In the animated series episode Gone Fishin` Jules Brown (one of Doc Brown's sons) places a spare flux capacitor in a barrel. When the barrel falls over the waterfall and reaches 88 mph, the flux capacitor activities and moves Jules ...


23

I hope I don't spoil the party with an out-of-universe explanation, but I thought that this was really interesting when I found it out: It was just supposed to be funny. The sequels weren't written yet. In the commentary on the DVD, Robert Zemeckis and Bob Gale explain the scene, that it was all just there for fun, including the "To be continued…". At the ...


21

This is all just speculation, but some points to consider: How many bottles of this “petrol” would be required to get to 88 mph? To what degree is this “petrol” compatible with combustion engines from 1985? There were no highways back then, where could you find a place to accelerate to the required speed? (If I remember correctly, flight was not an option.)


20

There's no logic explanation for this, it's just a plot hole created by the need of giving more tension on the end of the movie. Maybe if the horizontal wire could stretch a lot while the car runs after the connection with the hook, but i doubt it.


19

In the original timeline, when the movie starts and Doc tells Marty to meet him at the mall, he doesn't yet know if the experiment will work. Time travel in Back to the Future works by changing history, and at that point, no one had time traveled yet. In the new timeline, shown at the end of the movie, it's unknown whether all of the 1985 events from the ...


18

We know that the timer went off several seconds before Marty floored the accelerator. We know that Marty quite literally hooked the line at precisely the correct time. Therefore the only valid conclusion is that Marty accelerated faster than Doc calculated/anticipated/intended. Thus there are only two valid explanations: (1) Doc planned for Marty to ...


15

Maybe, but the Post Office wasn't involved. The package wasn't delivered by the United States Postal Service, it was delivered by Western Union, a private company. Speaking as a former postal employee, I would expect the US Postal Service to lose the letter sometime in that 70 years. They may eventually find it... but find it and deliver it on time? Not ...


13

They were going to try alternative combustible liquids. The first they tried was alcohol. The strongest one the could buy from the local bartender if I remember correctly. With that the intake manifold to blew out and then it would have taken about a month to repair it according to Doc. They didn't have the time for that since they were planning to leave ...


12

There are two logical ways of dealing with time travel paradoxes: Stable time loop. When you travel to the past, whatever you do, you won't actually change anything (which pretty much implies there is no free will). In fiction, the way this is often done is that the time traveller attempts to change the past, but doesn't succeed, because it was him who ...


12

It's a paradox. Predestination Paradox to be precise. The Lightning only strikes the Clock Tower because of the changes Doc and Marty make in order to harness the power of the Lightning Strike. The exact time of the Strike didn't matter, because while Doc and Marty are aiming for that exact minute based on the paper/their "history", whatever they actually do ...


11

Quite simply, it was never fixed. Lightning from an electrical storm struck the lightning rod above the clock tower and travelled down a cable which was wrapped around the metal hands on the clock face at precisely 10:04pm on November 12, 1955. The sudden jolt of electricity damaged the clock mechanism and it has never worked since. The Hill Valley ...


11

Who is to say they DIDN'T notice and comment on it... but we didn't see it? What would they have said anyway? Lorraine: Wow, Marty! You look just like a highschool friend of ours. (To George) Honey, c'mere! Look at Marty. Doesn't he look like that friend of yours, Kevin? George: You mean Calvin? Oh yeah, he does! Shame we don't have any photos ...


11

Marty was in the time machine when he came back. The definition of the time machine is that the machine (and what it contains) travel through time unaltered. (My real question would be, why is there just ONE Marty when he comes back to 1985 after fixing his family. There should be one Marty that was born from his parents on his normal birthdate, and one ...


11

He appears to have inherited it. When explaining to Marty where the flux capacitor came from I had a revelation! A vision! A picture in my head! A picture of this! This is what makes time travel possible: the flux capacitor! It's taken me nearly thirty years and my entire family fortune to realize the vision of that day


10

Whenever Doc Brown reaches an epiphany, he immediately sets to work to fulfill the context of said event. As an eccentric scientist, he has become accustomed to working in a high strung and over-driven manner, as he is always eager to have his projects come to fruition. With regards to what he concluded about Marty's children, he was alarmed by their ...


10

Because that wouldn't make a good movie. In reality they could have burned Kerosene that no doubt has a higher octane rating (150) than petrol of the time. With a low octane rating, they wouldn't have gotten to 88mph because the knock sensors would have cut timing and put the car in limp mode.


10

For an in-universe explanation: There may be sufficient capacitance in the system to allow the lightning charge to be stored for one minute. Doc Brown only knew the the lightning strike to +/- one minute, so it is logical that he would calculate the capacitance of the clock tower, and add additional capacitance to into the circuit to cover one minute of ...


9

Petrol wasn't invented until 1870 or 1871 and it seems likely it was a small potatoes British business. While I don't doubt that some of their product made it to the eastern U.S., it seems very unlikely it was well distributed and probably would not have made it to the Wild West, especially California. Even if it was sold in San Francisco, what are the ...


9

If Marty & Doc would have dug up the 1885 Delorean, then it wouldn't have been in the cave in 1955. Therefore the Marty in 1885 would possibly cease to exist.


9

The first (1988) draft of Back to the Future III supposedly has this scene, which was later cut in future revisions: Ironically, right then, Dean Wooster stops by with two other men named Cooper and Mintz. They tell Doc that, because he is working for them at the University (as a professor of physics!), he has to participate in one of three projects--...


8

Technically, in 1955, Doc Brown didn't invent time travel, he got the idea for the flux capacitor "which makes time travel possible." Doc Brown would first need to actually build a flux capacitor, and then he would need to work out how to use it to build a time machine. Just knowing that something is possible or that it will work, does not tell you how to ...


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