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The Time Travel Paradoxes of Back To the Future 454

Posted by CmdrTaco from the one-for-emmett dept.
brumgrunt sent in a fun little piece to get your brain going on a cloudy monday morning. Despite countless viewings of BTTF I still never thought of a few of these. "Throughout Back To The Future Part III, there has to be two Deloreans in 1885. Also, why don't George and Lorraine recognize their son? Why doesn't the time machine disappear in the alternative 1985? These and more Back To The Future paradoxes explored..."
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The Time Travel Paradoxes of Back To the Future More

The Time Travel Paradoxes of Back To the Future

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  • The one they always overlook (Score:5, Interesting)

    by elrous0 ( 869638 ) * on Monday October 25, 2010 @09:27AM (#34011180)

    If you travel back in time to the exact same spot, just in a different time, then (unless you're REALLY precise on the exact time of day and year), you'll most likely end up floating in space. People who make time travel movies don't seem to realize that the earth moves around its axis and around the sun. The spot I'm standing on right now will be vaccum in just a few minutes.

    If Marty had went back to a different time of year without a space suit, Biff would have been the least of his worries.

    • Re:The one they always overlook (Score:5, Insightful)

      by simcop2387 ( 703011 ) on Monday October 25, 2010 @09:31AM (#34011206) Homepage Journal

      Even if you're precise on the exact time of day and year you'll still be in space. the solar system moves too!

      • Re: (Score:3, Funny)

        by elrous0 ( 869638 ) *

        I picture a lone Delorean, forever floating through empty space at 88 miles per hour.

        • Frame of Reference Problem (Score:5, Insightful)

          by eldavojohn ( 898314 ) * <eldavojohn@noSpAM.gmail.com> on Monday October 25, 2010 @09:45AM (#34011344) Journal

          I picture a lone Delorean, forever floating through empty space at 88 miles per hour.

          I don't understand why you post first about a frame of reference problem and then joke about 88 miles per hour ... in reference to what? In the movies the DeLorean is traveling at 88 miles per hour as would be seen by an observer standing on Earth's surface. But to someone standing perfectly still in reference to the absolute center of the solar system -- as you seem to imply time machines are initially calibrated to -- then the velocity of the DeLorean would change with the velocity of the Earth around the Sun. Why are you only referencing the solar system and not galaxy or nebula or universe? So ... yeah, 88 miles per hour for those of us still on Earth many miles away. But your own post suffers the same problem that the movie suffers which is a frame of reference to the velocity and position.

          Basically for new writers who write a science fiction time travel story you gotta make sure you mention briefly that you solved the orbit/rotation/surface problem and have calibrated your time machine to account for the ever changing topography of the Earth as well as its orbit and rotation ... Or maybe claim that you machine is anchored to Earth's gravity well to simplify things a bit more?

          They were fun movies and nothing more. It might be fun to dissect them but if this is news, stand back in awe for my dissection of about a hundred other movies ...

          • Re:Frame of Reference Problem (Score:5, Funny)

            by elrous0 ( 869638 ) * on Monday October 25, 2010 @09:51AM (#34011394)

            I don't understand why you post first about a frame of reference problem and then joke about 88 miles per hour ... in reference to what?

            In reference to Einstein's dead body, of course.

          • Or maybe claim that you machine is anchored to Earth's gravity well to simplify things a bit more?

            The Earth's gravity well is also specific to a moment in time, as Earth changes structure internally and it constantly pulls in matter.

          • Re:Frame of Reference Problem (Score:5, Insightful)

            by fat4eyes ( 1233086 ) on Monday October 25, 2010 @10:19AM (#34011700)
            I don't even understand why this needs explanation. We all travel forward through time, and no-one needs an explanation of why we don't phase through the planet as time moves forward. Yet somehow traveling through time in a different direction (or at a different speed) will somehow cause you to end up in space. What needs asking is what does a time machine look like to the people in "normal" time when it is traveling backwards through time.

            • Re:Frame of Reference Problem (Score:5, Interesting)

              by maxwell demon ( 590494 ) on Monday October 25, 2010 @11:56AM (#34013292) Journal

              I don't even understand why this needs explanation. We all travel forward through time, and no-one needs an explanation of why we don't phase through the planet as time moves forward.

              Of course we need an explanation. Fortunately we have it: Because the matter below us causes a force on us (combined gravitational, elastic and friction), keeping us at "the same" place relative to the ground. For the very same reason there's no problem with H. G. Wells' time machine, because it's at its place all the time (he constantly sees the surrounding, just in another pace; of course that sort of time travel has its own set of problems, but that's another story), so it also should be subject to this force. However the time machine in BTTF (as well as the time machines in most stories/movies/series today) basically makes a jump in time, i.e. it simply isn't there in the intermediate times, thus there's no force which would keep it in place.

              Of course one could argue that since "the same place at another time" isn't exactly defined anyway, the inventor of the time machine must have built in some calculation of the relative position of earth at the destination, and manages to move the time machine to exactly that place. However, that should enable you to not only choose the time, but also the place where you appear (possibly restricted to the future/past light cone, but that covers all of the earth for any reasonable time travel; of course if you only travel a microsecond, your choices of reentry are severely limited). There's absolutely no reason then to restrict the time machine to enter at the "same" place.

          • Or maybe claim that you machine is anchored to Earth's gravity well to simplify things a bit more?

            Just imply that time and gravity are linked and your problems are over, the universe solves them for you! And since nobody has yet disproved this it's not even fantasy, although I certainly wouldn't call it hard sci-fi :)

          • Yea, I'm thinking anchored in our gravity well is the answer. If time travel is possible it will most likely be through traveling through time forwards or backwards and not an instant jump. Assuming all things constant, traveling backwards in time should allow you to have a constant velocity that matches the earth, though you may want to slowly ramp up the speed of your travel as two quick of a change could send your flying.

          • Re: (Score:3, Interesting)

            by Securityemo ( 1407943 )
            Actually, this problem is moot. As it happens, the absolute frame of reference in this universe defaults to the "sleeping" "body" of Cthulhu, in the "city" of R'hyleh, "located" on the bottom of the Atlantic Ocean here on Earth. So at most it's a difference of a few centimeters.

            (Seriously, this always disturb me on some visceral level when works of fiction discuss a universial frame of reference like there was such a thing? The relative frame of reference of "the universe"? Aeaeaeaeafhtagn...)

      • Re:The one they always overlook (Score:4, Insightful)

        by Pojut ( 1027544 ) on Monday October 25, 2010 @09:37AM (#34011268) Homepage

        We (my "main" circle of friends) discussed this very topic once after watching BttF 2. We concluded that anyone smart enough to create a working time machine (especially one that didn't turn its occupant into goop) was smart enough to do the mathematical calculations. ::shrug::

      • Re:The one they always overlook (Score:4, Insightful)

        by commodore64_love ( 1445365 ) on Monday October 25, 2010 @09:54AM (#34011424) Journal

        No you see, when you travel through time you still remain trapped inside the same gravitational "depression" in space. You remain at the same coordinates in the universe, and therefore still materialize on earth, because you're moving with the gravitational well.

        Otherwise if you could escape the gravitational well simply by advancing in time, you could jump have the NASA shuttle jump forward one day, and be in space, without needing to use boosters. That would violate conservation of energy and momentum.

        (tongue firmly planted in cheek)

        • But you still have the nasty problem of the changing geography and topography of Mother Earth. Not to mention the changing architecture - just one new building in the path of the DeLorean...

      • Re: (Score:3, Insightful)

        by shentino ( 1139071 )

        According to relativity, you never know if your absolute position is changing or not, or even if there is such a thing as absolute position.

        So if you time travel, whose reference frame do you use to advance yourself in time while remaining static in position?

    • It's not just the Earth thats moving around it's axis and then around the Sun but the entire Solar System is in orbit around the Galaxy and the galaxy is slowly moving as well... so yes unless you use some central point of reference you could end up anywhere, most likely in the vacuum of space or worse in some stellar core...

    • you'll most likely end up floating in space.

      You might also rematerialize inside earth's crust. I've heard this is good for acne, if you have any.

    • Re: (Score:3, Interesting)

      by Drakkenmensch ( 1255800 )

      If you travel back in time to the exact same spot, just in a different time, then (unless you're REALLY precise on the exact time of day and year), you'll most likely end up floating in space. People who make time travel movies don't seem to realize that the earth moves around its axis and around the sun. The spot I'm standing on right now will be vaccum in just a few minutes.

      John Carpenter is the only director I can think of who ever complements his time travel explanation (albeit for a radio signal, but still) with the earth's revolution around the sun: http://en.wikipedia.org/wiki/Prince_of_Darkness_(film) [wikipedia.org]

    • Worse yet, suppose you traveled back in time but arrived inside the earth! One of the worst things in Wizardry was teleporting your party into a solid wall. That was instant death, no recovery. Talk about a real bummer!

    • This particular problem can be sidestepped. Earth (and the Solar system) moves along geodesics in 4D-space (that's what the whole General Relativity is about), so we can just imagine that your time machine will also move along geodesics (essentially, retracing the path of the Earth and Solar System) when traveling in time.

    • Re: (Score:2)

      by dbet ( 1607261 )
      It depends on how you view the act of time travel. It's not unrealistic, if you've already conceded the possibility of time travel in the first place, to imagine you still adhering to the physics of the world you're in and spinning with the earth as it moves. You still might end up say, a few inches above or below the ground, or stuck half-way in a house or something.

    • The spot I'm standing on right now will be a vaccum in just a few minutes

      That depends entirely on your coordinate system.
      If you use the origin at the centre of the earth, y up, x towards the GMT line, then no it won't (I hope).
      If you use the sun as the origin and pretty much any orientation, then yes it will.
      If you use the centre of the universe, then god knows.

      Bob

    • What I don't understand is that people like you aren't intelligent enough to realize that a man like Doc Brown, who's smart and skilled enough to build an actual working time machine wouldn't be smart enough to compensate for the spatial displacement.

    • Re:The one they always overlook (Score:5, Insightful)

      by mea37 ( 1201159 ) on Monday October 25, 2010 @11:29AM (#34012808)

      Well, according to Einstein's description of gravity this may not be such an issue as you think. The Earth's movements are, after all, governed by gravity. Now gravity doesn't so much "curve" an object's course, as it bends spacetime around the object's path (which is a straight line).

      And you're here on the Earth's surface, so you're moving along the same line. You hop in your car, start deviating from the straight-line path by 88mph, and then... what, exactly?

      Your post (and many people's intuition) assumes that you suddenly change velocity in all dimensions, so that you move in time but stay at a fixed position in space. The problem is, the concept of a "fixed point in space" is a figment of human imagination; there's no such thing. A fixed point in space implies a prefered frame of reference, and there simply is no such thing.

      So what spacial trajectory does the time machine follow? Well, why would it not continue moving at 88mph deviation from the straight-line path through curved spacetime that it's already following - that being the same line being followed by the Earth?

      Gravity would cause the time machine to "follow" the Earth as it moved through time. Not the Earth's gravity, as many other posters have suggested, but rather the Sun's gravity and the other various forces that move the Earth.

      There are many, many, many problems with time-travel fiction, but the idea that you would be lost in space just isn't one of them.

    • Simple explanation... (Score:3, Interesting)

      by denzacar ( 181829 )

      Note the portal forming in front of the Delorean just before it disappears. [youtube.com]

      Delorean is PUSHED through a portal created by the flux capacitor which actually exploits naturally occurring folds in the space-time by poking a tiny hole (from the universe's point of view) in those folds for a fraction of a second.
      Delorean needs to be moving at 88 mph in order to get to the other side in one piece before the portal closes.

      So you see... it is more like the Star Gate than like H.G. Wells' time machine.
      Now, that one

    • Re: (Score:3, Interesting)

      by JWSmythe ( 446288 )

      That's something I always loved about time travel. They never mention spatial teleportation. To accomplish time travel, there must be spatial teleportation to arrive in the same place on a planet. Say your time machine was in Times square, and for some reason you were spatially oriented on the center of the planet, and you attempted to travel 3 hours to the future, when you arrived, you'd arrive somewhere between Gerlach, NV to Ravendale, CA. If you aren't spatially centered on the planet

  • someone fire up their CGI skills and make it like it should be and rewrite a few lines of the script

  • Despite what who? (Score:5, Funny)

    by UncHellMatt ( 790153 ) on Monday October 25, 2010 @09:34AM (#34011248)
    "Despite countless viewings of BTTF I still never through of a few of these. "
    Did you the whole thing?

  • Of course there are two DeLoreans (Score:5, Interesting)

    by rarel ( 697734 ) on Monday October 25, 2010 @09:37AM (#34011270) Homepage
    Of course there are two Deloreans. Doc's and Marty's. It's not a plot hole at all, the whole point is that they can't gut Doc's DeLorean for parts since it would create a paradox and prevent Marty from going back in time to 1885.

    The cool thing is that at one point there are FOUR DeLoreans for a few hours in 1955, Marty I, Cowboy Doc, Marty 2 (with Doc) and Biff's.

    • Re:Of course there are two DeLoreans (Score:4, Funny)

      by chemicaldave ( 1776600 ) on Monday October 25, 2010 @09:51AM (#34011396)

      The cool thing is that at one point there are FOUR DeLoreans for a few hours in 1955, Marty I, Cowboy Doc, Marty 2 (with Doc) and Biff's.

      Delorean actually made that many DMC-12s?

    • The cool thing is that at one point there are FOUR DeLoreans for a few hours in 1955, Marty I, Cowboy Doc, Marty 2 (with Doc) and Biff's.

      Marty 2 prefers to be called Marty A

  • The gasoline crunch (Score:4, Interesting)

    by Drakkenmensch ( 1255800 ) on Monday October 25, 2010 @09:38AM (#34011282)
    Doc probably could have MacGuyvered a distillation setup to make gasoline out of petroleum, but he quickly figured that it would take him much longer than it would take for him to get murdered and so other options were needed. He just didn't bore Marty with the details and called it impossible, adding the words "in what little time we have" in his own head.

    • Doc probably could have MacGuyvered a distillation setup to make gasoline out of petroleum, but he quickly figured that it would take him much longer than it would take for him to get murdered and so other options were needed. He just didn't bore Marty with the details and called it impossible, adding the words "in what little time we have" in his own head.

      Being such an amazing genius he should have realized that he could use Butanol [wikipedia.org] as a direct gasoline replacement. It's been produced by bacteria on an industrial scale since 1916 [wikipedia.org]! Doc fail.

    • Completely negating the possibility of just hiding the Delorean and skipping town for a while . . . .

      All they would have had to do is quietly LEAVE. Go somewhere else, and take the Delorean with them. It's 1885. Unless they're not being discrete it's darned hard to find someone who doesn't want to be found, and my guess is Beaufort, seemingly being the short attention-span type of guy, probably wouldn't have kept looking for too long before an "Ohh, shiny!" caught his eye and he went off chasing something

      • Re:Being discrete (Score:5, Funny)

        by markhb ( 11721 ) on Monday October 25, 2010 @10:33AM (#34011932) Journal

        I don't believe that there is any possible frame of reference that contains an intersection of "being discrete" and "take the Delorean."

        • Re: (Score:3, Insightful)

          by MBGMorden ( 803437 )

          They were dragging it around with horses and no one noticed. There's a LOT of open country with no one around back then. Worse case scenario, hook the horses up again, throw some brown burlap over the car, and ride on top of it like a buck-board. I seriously doubt anyone would notice a thing from a little distance, and once they get where they're going they can simply hide it as they did previously.

    • so other options were needed

      Like going out to the DeLorean that Doc had stashed in the mine and siphoning some gas out of its tank?

    • That's one solution. The other being more or less what he did do, which is leave some hints for Marty in the future. This one is definitely the simplest way of handling it, although for reasons related to plot development Marty forgets to top off the tank before going to retrieve the doc.
    • I thought about this a long time ago, actually. It always bugged the crap out of me that they spent much of the third movie driving to the point that the time machine is a terrible thing and must be destroyed before it tears the universe a new one. At the end of the movie this is accomplished splendidly, only to immediately find that Doc Brown has created a new one.

      Instead of a fourth movie, I propose a short series. The story is that Marty realizes that Doc Brown must be stopped, so he teams up with the
      • Except what they don't ever really talk about is that each time they double the Martys or the docs in a given point in time, they double the amount of time that period in history takes up. Shortening their useful lifespan by that much. Since they've already lived in that stretch of time doesn't automatically tack that on to the end of your life.

        Consequently, they would be aging significantly with respect to everybody else in their original time line. For a few relatively short trips it's not a big deal,

  • Words of Wisdom from UHF Television of the era (Score:3, Insightful)

    by Anonymous Coward on Monday October 25, 2010 @09:44AM (#34011332)

    Repeat to yourself: It's just a show, I should really just relax.

  • Jennifer seeing herself... (Score:4, Interesting)

    by Anonymous Coward on Monday October 25, 2010 @09:44AM (#34011336)
    Regarding Jennifer's surprise at seeing herself, the older Jennifer is surprised because they see each other at the same time. Up to the point young Jennifer sees old Jennifer, old Jennifer can't remember seeing young Jennifer because it's not a done deal yet. Time is still in the process of being changed. The movie is pretty clear that changes to the timeline are not predetermined. Old Jennifer cannot remember seeing young Jennifer until it actually happens, thus being a surprise for both parties.

    • Re: (Score:2)

      by alen ( 225700 )

      over the years i've noticed that faces aren't unique. i've met at least one person in my life who looked almost exactly like me and as far as i know we weren't related. even though a few people started wondering since the resemblance was so close. my wife is often compared to a minor hollywood actress.

      and if you look closely at 500 year old paintings or statues of ancient greeks and romans they look just like people do today. one time when i was in italy i saw someone who looked just like Jay Leno. and look

    • Re: (Score:2)

      by Ecuador ( 740021 )

      Also it has to do with another point in the article. While Jennifer is in the future, there is no Jenifer in 1985 to grow old, another paradox. Although I strongly advise against trying to rationalize the plot of this amazingly entertaining trilogy, the way I think we should explain it keeping in the spirit of the movies is: The future is as it would be had the Delorean not traveled in time, at least for a while, since the events that would happen during the visit in the future had not happened yet. Let's n

    • It's the timey wimey wibbly wobbley....

    • Re:Jennifer seeing herself... (Score:4, Funny)

      by kellyb9 ( 954229 ) on Monday October 25, 2010 @11:41AM (#34012990)
      She's probably just shocked that she looks nothing like what she looked like in the first movie.

  • The universal answer to these questions (Score:5, Funny)

    by FranTaylor ( 164577 ) on Monday October 25, 2010 @09:47AM (#34011372)

    Can be found in a "Rocky and Bullwinkle" episode from long ago.

    Boris Badenof has just cut the rope on a large treasure chest that dangles over a cliff. Of course he is standing on the treasure chest at the time so they both fall together. In typical comic form the treasure chest inverts as it falls, so Boris is underneath it as it crashes to the ground.

    Natasha cries out, "Oh Boris are you okay?"

    Boris says in response: "Don't worry, tis only cartoon".

  • Logically, Marty's parents would have had a fight about Lorraine having cheated on George with Calvin Klein well before Marty reached that stage in his life. There's no reason they suddenly would have had that fight on the exact day Marty came back from 1955.

    • Re: (Score:2)

      by Nursie ( 632944 )

      What I came here to say.

      George would be convinced that she'd tracked down this Calvin Klein and had some out-of-wedlock with him.

  • Separate Time Lines (Score:4, Interesting)

    by crndg ( 1322641 ) on Monday October 25, 2010 @09:55AM (#34011438)

    There are many different ways time travel can be presented in fiction, with many different sets of "rules." In my opinion, BTTF actually sticks pretty close to its own rules, except when a) absolutely necessary for the story, or b) good for a laugh (see a).

    The reason future versions of people don't know what's going on right now in their being-rewritten past is because they're in a different line on Doc's chalkboard. So when Doc in 1885 writes the note to Marty, he is from a future where (when?) he didn't know he was going to be killed by Mad Dog Tannen. So he couldn't possibly know that Marty was going to need to come back and rescue him, and would need gasoline to do it.

    As for why Marty's parents don't recognize him, I would say they've had years to forget the details of what Calvin Klein looked like, and years of seeing their son every day as he grew up to look like someone they haven't seen in 30 years. Think of someone you know and see often. Now look at a picture of them from a long time ago. In your mind, they may seem like they haven't changed, but they have. It's like how I still picture my dad looking like he did a while back, when I saw him more often, and am now shocked to see that he has turned into Rush Limbaugh (not literally, but eerily similar-looking).

    The one good question posed by this article is about whether Marty and Jennifer would exist in 2015, after they have just gone off in the time machine w/ Doc Brown in 1985. At that point, we might think they should be removed from any future time line until they return safely to 1985. I can only surmise that when traveling to the future, the Delorean travels along the future time line it is leaving, without regard for any changes it may introduce by doing so.

    Perhaps a better overall question is: what happens to all the versions of people stuck on those time lines that are then cancelled out by Doc and Marty's travels? Do they zap out of existence? Do the time lines continue on, with fake-boob Lorraine married to Biff and all the other unpleasantness? Should we be happy that everything worked out for "our" Marty, because he's the only character who is the same person we met at the beginning of the first movie?

    • Re: (Score:2)

      by rarel ( 697734 )
      The one good question posed by this article is about whether Marty and Jennifer would exist in 2015, after they have just gone off in the time machine w/ Doc Brown in 1985. At that point, we might think they should be removed from any future time line until they return safely to 1985. I can only surmise that when traveling to the future, the Delorean travels along the future time line it is leaving, without regard for any changes it may introduce by doing so.

      The author fails to realize one key point, the

  • There's no guarantee that the scores in the book would hold up if the timeline was altered. You all saw what happened in the Bronco's game on "Hot Tub Time Machine", right? Biff would probably still end up a broke loser, because the chaos of the universe would alter people's actions in small ways that would eventually cause huge changes in outcomes.

    • Re: (Score:3, Insightful)

      by tophermeyer ( 1573841 )

      From what I remember from BTTF II Biff had made most of his fortune making big bets on upsets for just the first few years, then started rolling his fortune into his casino. That's why he had the Sports Almanac shrink wrapped in a safe in 1985, even though it contained sports scores through 2001.

  • 2 Pines Mall/Lone Pine Mall (Score:4, Informative)

    by Knightman ( 142928 ) on Monday October 25, 2010 @10:00AM (#34011496)

    It's quite funny how many paradoxes there are in BTTF, and still they managed to put in some truly obscure consistency: http://www.thevrabec.com/2010/07/12/back-to-the-future-you-certainly-havent-noticed-this/ [thevrabec.com]

    • Was this not an obvious gag? These guys seem genuinely surprised to have discovered this just a few months ago, claiming "you certainly haven't noticed this." I figured most people had picked up on the "You killed my pine" joke years and years ago.

      I see mentions of it on the internet way back into 2000, and it was already regarded as old new then. Yikes.

      Still, it was a clever joke.

      • i didn't notice the lone pine thing till i was a teenager, possibly due to the fact that up till that point i thought old man peabody was shouting "you'll kill mankind!" :D

  • wait wait wait! (Score:5, Funny)

    by 192939495969798999 ( 58312 ) <[info] [at] [devinmoore.com]> on Monday October 25, 2010 @10:03AM (#34011514) Homepage Journal

    You mean to tell me that in the movie about the time travelling, flying delorean, that runs variously on a fusion engine and stolen libyan plutonium, that there's something unrealistic about the plot of that movie? NOOOO!
    haha.

  • Time travel paradoxea worked different in the 1st one (you vanish from photos, or you cant touch guitar) from the second (alternate realities, universe exploding) and the third (marty still know the name of the teacher, the tombstone picture)

  • The one nobody thinks of... (Score:3, Insightful)

    by Dr. Manhattan ( 29720 ) <(moc.liamg) (ta) (171rorecros)> on Monday October 25, 2010 @10:24AM (#34011790) Homepage
    What happened to the Marty who grew up with a go-getting SF-author father?

    Of course, I've thought about time travel more than is healthy [homeunix.net].

  • Science Fiction authors have known for a long time that time travel can create paradoxes. There are many better efforts than the BTTF series however. (Of course BTTF was never intended as 'serious' science fiction. Even Star Trek has done a better job.

  • The Doc Would Know He's Going To Die ... at the very point that the Doc and Marty uncover, in 1985, that 1885 Doc has been killed by Buford Tannen, that should have stopped Back To The Future Part III dead. After all, the sole reason Marty goes back to 1885 is to save the Doc.

    So,why would it have killed the film? Well, at the start of Back To The Future Part III, we see the 1955 Doc, who is the younger version of the character. The Doc who got sent back to 1885 is the older one. Thus, at the point the young

  • I'm not sure I follow his reasoning. He seems to be saying that because Marty and Jennifer are in the future, that they haven't returned to the past yet to be present in 2015. Therefore, while they're "out of time", they're essentially gone from the normal flow of time.

    I see a few problems with this analysis. First of all, the 2015 Marty and Jennifer are their futures. They've long gone to the future and come back by that point.

    When Einstein was transported a minute into the future, it was only a one-way tr

  • Remembering 'Calvin Klein' (Score:5, Insightful)

    by j-beda ( 85386 ) on Monday October 25, 2010 @11:06AM (#34012488) Homepage

    The article states: "Even appreciating that they didn't know 'Calvin Klein' for long, his impact upon them was such that they'd still have an idea what he looks like, many years later."

    I think the author overestimates how much visual memory is likely to fade after 30 years. I just saw some high school classmates after 25 years and looked over some old HS photos. I could barely recall the linking between HS photos and names of the people I saw daily for over three years - including some I lusted after with all the strength of a stereotypical adolescent. Without photographic backup (did Marty get in any photos at the dance?) I doubt they could remember his look very well after only knowing him for a week or so. Combining this with later knowing Marty's face since birth and gradual growth, I do not find it at all implausible that they wouldn't recognize his as a teenager as looking like "Calvin".

  • Gasoline (Score:3, Insightful)

    by plopez ( 54068 ) on Monday October 25, 2010 @01:32PM (#34014850) Journal

    As far as the gasoline aspect goes, you would need the right *kind* of gasoline. I can't find the compression ratios, but the De Lorean would probably need high octane gasoline and since it was in the US it would need a catalytic converter and unleaded gas. There would be more complications if it had a turbo. You would have to reinvent all the chemical processes to create such a fuel. It might be simpler to create a a fuel using local materials such as coal, nitroglycerin, gunpowder etc. like The Doc did. He could have used them to create a sort of HME, rocket fuel, which burns very hot. But that creates the question of why didn't he just make a couple of RATO packs? The Diesel engine was out since it wasn't invented until 1897 and may have required precision machine work.

    Just a few thoughts.

  • Paradox (Score:5, Funny)

    by digitalsushi ( 137809 ) <slashdot@digitalsushi.com> on Monday October 25, 2010 @01:47PM (#34015078) Journal

    When Doc is talking to himself in 1955, I am pretty sure he created a pair of docs.

  • Gasoline (Score:3, Insightful)

    by X86Daddy ( 446356 ) on Monday October 25, 2010 @02:35PM (#34015714) Journal

    As a kid, I wondered why they didn't just get gasoline from the stored-in-a-cave DeLorean. I don't wonder any more though. Any DeLorean owner will tell you, don't leave the car sitting with the same gasoline more than six months, especially without a fuel stabilizer. I doubt the Hill Valley General Store stocked Sta-bil in 1885, so I'm guessing Doc Brown drained it.

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