when Doc and Marty are in the future, old Biff goes back in time and gives the almanac to young Biff, but nothing in 2015 changes....but then Doc says later that after they fix everything, the world will change around the unconscious Jennifer....so why didn't the future change to reflect a world with a super-rich Biff? I thought the street should change a little....or maybe it did and I didn't notice....did any signs change to say, "Tannen Estates"?

Presumably it did change. Remember that Doc and Marty left in a big hurry, and they were in a bad neighborhood to begin with. We didn't see downtown Hill Valley in 2015 after Biff stole the Delorean.

That's the best way I can explain it.

I agree with greatjedi here. Since Marty and Doc left right after Old Biff came back, they weren't around long enough to see the changes. But who knows, maybe things wouldn't have changed in that particular neighborhood.

I think you're all forgetting Doc's explanation of events in the altenate 1985 on the chalkboard. Remember, he explains that when Biff went back to 1955 an alternate time line was created and that's where they ended up when they "returned" to 1985.

However, now that I think about it, that does beg the question, how did they jump realities and 2015 not change? I can understand Doc's split explanation, but then how they arrived at the alternate time-line is a mystery. Good question.

Unless of course it has something to do with other settings in the DeLorean that we are unaware of. Is there any sort of commentary on this? I haven't watched my II and III discs yet. I've been meaning to send them in to get the correct versions, but haven't done so yet.

I think it was because they were in the future of the un-altered (Biff has almanac) timeline and it would stay that way. Although the world changing around Jennifer quote kinda messes that theory up.

Remember the diagram Doc Brown does in his laboratory in the alternate 1985? He showed two lines, one with the "normal 1985" and one with the "alternate biff 1985". Since they were in the normal 1985 when they went to 2015 they could have spent the rest of their lives there and not have it affected by the spliting off of time that old Biff created when he gave the almanac to his former self in 1955...and good lord I've gone cross eyed.

Do none of you watch the deleted scenes? In one of them it shows Old Biff dissapearing after he got back from 1955. If memory serves they never explain how or why he does dissapear(I saw this on that 'making of Back to the Future tape with Kirk Cameron..ive yet to watch the DVD deleted scenes). It's assumed that Loranne shoots him sometime in the 1990's. So if Biff is dead in 2015 after giving himself the Almanac in 1955 that would start a chain reaction of events that would ultimately lead to his demise. No Alternate Biff..no Alternate 2015...one would have to assume...hmm?

Deleted scenes=not a part of the story.

Deleted scenes = WAS part of the story but cut out for time, or simply to leave the audience to come to their own conclusions.

In terms of plot and explanation, deleted scenes don't count. Especially considering 90+% of the public will never see it.

I believe the widely accepted theory is that things changed around them while they were in the future.

Obviously they couldnt change based on the things that Biff did or it would cause a paradox

Marty & Doc wouldnt meet thereby canceling out all of the first movie. Also Doc would have been committed so he couldnt build the time machine which wouldnt lead to Part 1 which wouldnt lead to them even going to the future for Biff to travel back to change things.

And as for Doc's line about 1985 changing around Jennifer...i believe he meant that she wouldnt even know that the "bad" 1985 exsisted.

At first I thought things didn't change because they were in an alternate timeline, but that doesn't work because if that were the case Doc's telegram never would have reached Marty at the end of the film. So, it seems that the world changed but not that neighborhood OR changes are slow to take place (the gradually dissolving photos in the first film).

I'm with greatjedi and zekeburger1979 on this one.

Something else I've recently noticed about this - in the alternate timeline George McFly is killed sometime in the 1970s I believe. You will notice that after Biff steals the Delorean, you no longer see old George McFly in 2015. (Presumably, because he couldn't be there anymore as he died 40 some years ago.)

How did marty have children?
And how was he even in 2015,
Being he left 1985.

2015's future should should not
have included Marty.

Many paradox's in these movie.

You'll enjoy it a lot more if you don't read so much into it.

Although Doc draws two distinct timelines, the movies show that these are overlapping "fuzzlines"... i.e. one morphs into the other over a period of "meta-time"... i.e. a length of "time" unrelated to the time line.

Evidence? The shifting photographs. Marty had time to save his parents marriage and thus restore the photograph to it's original state. The speed of change seemed to reflect probabilities. i.e. he was slowly disappearing at first, but when he saved the marriage it popped back quickly.

SO, when Old Biff gave young Biff the almanac, it took time for the change to affect the entire time line - for that fuzz line to move from reality 1 to reality 2.

Personally, I can't wait for "The Butterfly Effect" movie to come out.

Sorry, but what does that have to do with this thread??!!!!

If masetodd is talking about what i think he is talking about then he is refering to a time travel movie that deals with events affecting more than one localized area (Like Hill Valley)

Go back and inspire Elvis to become something other than a musician and you would effect all music from the mid-50's on. Musicians who were inspired by Elvis wouldnt have been inspired and they wouldnt go on to inspire others.

Its a snowball effect

Well that's cool if that's what he's talking about.

But he needs to say so and elaborate on it! =)

Just to add one thing with your explanation. Remember in the first movie? That picture of Marty's brother and sister? Once something is change that will alter the future, the things at the present time will change SLOWLY!! Once Lorrane was in love with Marty, first thing happend was Marty's brother's hand SLOWLY disappear then was his body then goes onto Marty's sister. Thus, once old Biff gave the young Biff the almanac, things did begin to slowly change. Biff didn't disappear until he got back to 2015 and Doc and Marty left so fast, immediately after Biff got back that they simply hasn't allow the changes to take place.

Or is it a contract issue at the time this movie was filmed??

Hint: go watch the special feature of the DVD.

Plus isn't Biff having problems getting out of the car in the future when he returns the car? That is was was "better" explained in the "secrets of BTTF" special w/ Kirk. Since that IS in the movie, the special simply explained why he was having problems (Ie dead in the future?)

All this off the top of my head, waiting til a B&M gets V2.

Old Biff disappears when he returns back from 1955.