Right. They didn’t get transparent aluminum from him; they just traded the formula for the thick plastic sheet they needed.
Hello! McFly!
That was so much fun! Thanks! Now I’ll go watch more episodes.
It happens all the time on 24. 
The DeLorean wouldn’t have worked because the navigation system was flawed. There was no “Year Zero”; the Romans didn’t have that concept. The Julian/Gregorian calendar, which we still use today, went directly from 1 BC to 1 AD. This is why the 21st century began in 2001, not 2000.
As an aside, the phases of the Moon were wrong in E.T. Scientific accuracy has never been Spielberg’s strong point.
Also, Jesus almost certainly wasn’t born on 25 December.
I don’t see how that’s an issue. You’d only need to know the present time and the destination time, and you don’t need a year zero to calculate the difference between the two.
Edit: unless of course you want to travel to BC. Maybe that’s the limit. Or maybe you just need to program the computer correctly to skip from 1 AD to 1 BC. Seems like, given all the other impossible technology, that part would at least be relatively simple.
The clock settings would have been completely wrong. How can you navigate when your coordinates are flawed?
Watch Longitude sometime and you’ll see what I mean.
I’m not sure what I’m missing, but the way I see it, the system only needs to know how far to move backward or forward through time. And the difference between 1985 and 1955 is the same whether there’s a year zero or not.
That was how Welles’ time machine worked. It had a joystick and was obviously an analog system that didn’t depend on the initial setting
With Doc’s machine, the destination was set digitally: Present Date–Target Date. If the clock was wrong, the system wouldn’t know what year it was to begin with.
Sure, but there’s lots of ways to initially tell the system what date and time it is. You wouldn’t calibrate from zero; you’d calibrate from the present. So you’d calculate the destination relative to the present. Unless you’re crossing the BC/AD line, no problem.
Doc Brown sets the flux capacitor to December 25, 0000, as he’s telling Marty, “Say you want to witness the birth of Christ.”
I forgot about that part. Still (despite the fact that Christ, if he did exist, was almost certainly not born on December 25th), you’d get to the correct date anyway relative to 1985.
I concede that if you went to any time before 1 BC, which the computer apparently considers “0000”, then you’d be off by a year. That’s a stretch from claiming it “wouldn’t work” for that reason.
There was no “Year Zero.” How can you enter a target date that doesn’t exist?
If you entered “1985 minus 1,985 years,” you’d end up in 1BC. Which wouldn’t be the year of the Nativity, even if Christ had been born 1,985 years previously, which he almost certainly wasn’t.
Anyway, that wasn’t how coordinates were entered in Doc’s machine. You needed a specific day, month, and year that actually existed.
I think even within the context of the movie, we weren’t supposed to think that Doc Brown actually intended to go to December 25, 0000.
I agree. He had to know that there would be no way to get to the birth of Christ, given the DeLorean’s inability (at the time) to fly or swim; ergo, he was kidding. Actually trying to get to that date would likely generate an error.
Yeah, you would need the geographical coordinates as well.
There’s a lot more to time travel than is generally appreciated. F’rinstance, not only are the geographical coordinates different today (because of plate tectonics), the Earth itself is not in the same position relative to the rest of the Galaxy (or anything else, for that matter).
I still have a few boxes full of these guys, if anybody is interested. 
(Just kidding! 
)
Pardon me but you seem to have mistaken the DeLorean for a TARDIS.
Because the targeting system doesn’t have to know, or care, what the year was actually called - only that is was 1,985 years ago. Entering “0000” lands you in 1 BC. Entering “-0001” lands you in 2 BC. So what?
The first movie is a near-perfect masterpiece. I have a soft-spot for the 2nd, and the 3rd is great from a character development perspective, but kind of a bore otherwise. It does nicely bring the whole trilogy full circle, though.
Recently shared the trilogy with my kids, who usually call anything made prior to 2010 “old-timey”, and even they loved the first one. They liked the second one once it got out of “2015”, which they couldn’t stop laughing at. The third, I think they also found a bit boring. (We’re just not a Western loving family, I guess.)
There were some uncomfortable moments in the 1st one to watch with kids, but they led to some worthwhile conversations, I think. (“Why was George trying to look in Lorraine’s window?” “Why is Biff trying to kiss her if she doesn’t want to? That’s not OK!”) (see also alt-1985 Lorraine’s “enhancements” in part II…)
You have to wonder what Marty 2’s life would be like. The George in the first movie was extremely timid and easily gave in to fear rather than any confrontation. We see that both in 1985, and when Marty first goes back to 1955. Marty 1 helps George learn how to confront those fears and as a result he becomes a confident success.
Marty 2 grows up in a house with a confident father who also recognizes the temptation of doing nothing. I could imagine a George who, when tempted to do nothing, says “what are you George, Chicken?” and then proceeds to do what he set out to do. This could be both an inside joke in the family, and a mantra to never give in to fear no matter what.
Somewhere between the first movie and the second movie, I think the first Marty we knew merged with Marty 2. This is why we suddenly see character traits that were never mentioned in the first movie like never allowing himself to be called chicken. It would be interesting to quiz him to see what his youth was like, but given that the George and Lorraine in 2015 appear to be the successful versions of themselves it stands to reason that that entire family has always been in that timeline.
Or you stay right where you are and the display puts out “ERR ERR ERR”, as with trying to get a calculator to divide by 0.