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The Science and Physics of Back To the Future

overthinkingit writes "A scientist has tried to apply serious math and physics, including the Law of Cosines, to analyze how the DeLorean in Back to the Future travels through both Time AND Space: 'in order to pull off the kind of time travel we see in the Back To The Future trilogy — the kind where the traveler is transposed in time, but remains stationary in the same relative position to where he/she left — the DeLorean would have to be an outstanding space ship, in addition to its already laudable work as a time-ship. According to Doc Brown's stopwatch, Einstein the dog travels precisely one minute into the future on this first jump, arriving, relative to their frame of reference, at the same location he left. But how far has this reference frame itself traveled during that one minute?'"

43 of 436 comments (clear)

  1. Does it explain by oodaloop · · Score: 5, Funny

    how it leaves tracks of fire on asphalt? Or in the air? Never quite understood that part. The rest of the movie, OTOH, makes perfect sense.

    --
    Tic-Tac-Toe, Global Thermonuclear War, and relationships all have the same winning move.
    1. Re:Does it explain by overcaffein8d · · Score: 3, Interesting

      i know it was a joke, but i watched the special features on the DVD, and they said that they just thought that it'd be cool if it was hot when it left point A in time and was cold when it got to point B (they put liquid nitrogen in on scene)

      --
      Those of us who think they know everything annoy those of us who do.
    2. Re:Does it explain by Anonymous Coward · · Score: 4, Funny

      Ironically Doc Brown knew his machine could travel through time, yet was surprised the car was cold.

      He would have been more surprised if Einstein was turned inside out in the front seat.

    3. Re:Does it explain by KJSwartz · · Score: 3, Informative

      It was a well-known observation that Dr. Brown sent Einstein back one minute in time to Calibrate the DeLorian's Space-Time compensator. Since the terrorists showed up before the calibration could be validated, Dr. Brown's compensator was calibrated 2-3 picometers into the substrate.

      Notice in Revision 2 (the Locomotive), there were no contrail.

  2. It's really quite simple by Diss+Champ · · Score: 5, Interesting

    The universe really DOES revolve around the earth in the movie universe, so no special measures are necessary beyond "simply" moving in time.

    1. Re:It's really quite simple by gmuslera · · Score: 4, Funny

      Beware... you could end in "All you zombies" version of RAHeinlein time travel, and you will enjoy twice meeting with your mother.

    2. Re:It's really quite simple by MaskedSlacker · · Score: 5, Funny

      And by meeting, he means fucking.

    3. Re:It's really quite simple by MobileTatsu-NJG · · Score: 4, Insightful

      Nah, it was at the beginning of the first movie when he was showing off how the input panel worked.

      This is a messy discussion. They don't address the problem and they don't not address the problem. I mean, if you wanted to argue against my point, you could mention that the ability to precisely place the vehicle in the same relative point on Earth would also mean he had the ability to any point in the universe instantaneously. Seems like he'd be even more excited about that than time travel.

      Makes the ol' head hurt. ;)

      --

      "I like to lick butts!" by MobileTatsu-NJG (#32700246) (Score:5, Informative)

    4. Re:It's really quite simple by Chris+Burke · · Score: 5, Funny

      Which is redundant when talking about the works of Heinlein.

      --

      The enemies of Democracy are
  3. Doesn't need to be a spaceship by Yvan256 · · Score: 5, Insightful

    Since it was in space for 0.0000E+999 seconds, i.e. never.

    It did travel in time and moved from one point to another in the universe (to stay in the same spot on earth) but it didn't "travel in space", hence no need to be a spaceship.

    1. Re:Doesn't need to be a spaceship by shaitand · · Score: 5, Insightful

      'So, think about it... if you moved through time, forward one minute, and somehow skipped any spatial movement, the earth is going to be AT LEAST 1000 miles away from the point, relative to JUST its movement around the sun. That says nothing about how our solar system is moving through the galaxy or the galaxy moving in the universe.'

      I think you misunderstood his point. Yes being at the same location on earth requires a spacial movement. But in back to the future that movement is instantaneous just as your movement through time is. You never actually occupy the space in between and are never in outer space. There is no reason the delorian must be pressurized or carry oxygen tanks, exercise equipment, etc like a 'space ship'.

    2. Re:Doesn't need to be a spaceship by EllisDees · · Score: 3, Insightful

      I think the problem is that there is no universal frame of reference that you are moving through. Sure, the Earth is spinning, the galaxy is rotating, etc. - but without some force acting on whatever is moving through time, it would follow the exact same trajectory as the surface of the planet.

      --
      -- Give me ambiguity or give me something else!
    3. Re:Doesn't need to be a spaceship by Cederic · · Score: 4, Insightful

      So when travelling back in time, the car moves forward to where the Earth would be as far into the future as the car went in the past - while the earth in the past hasn't reached where it was in the present yet.

      To go back in time inertia is insufficient.

    4. Re:Doesn't need to be a spaceship by Talderas · · Score: 3, Insightful

      Whenever life gets you down, Mrs. Brown,
      And things seem hard or tough,
      And people are stupid, obnoxious or daft,
      And you feel that you've had quite eno-o-o-o-o-ough...

      Just remember that you're standing on a planet that's evolving
      And revolving at nine hundred miles an hour,
      That's orbiting at nineteen miles a second, so it's reckoned,
      A sun that is the source of all our power.
      The sun and you and me and all the stars that we can see
      Are moving at a million miles a day
      In an outer spiral arm, at forty thousand miles an hour,
      Of the galaxy we call the "Milky Way".

      Our galaxy itself contains a hundred billion stars.
      It's a hundred thousand light years side to side.
      It bulges in the middle, sixteen thousand light years thick,
      But out by us, it's just three thousand light years wide.
      We're thirty thousand light years from galactic central point.
      We go 'round every two hundred million years,
      And our galaxy is only one of millions of billions
      In this amazing and expanding universe.

      The universe itself keeps on expanding and expanding
      In all of the directions it can whizz
      As fast as it can go, at the speed of light, you know,
      Twelve million miles a minute, and that's the fastest speed there is.
      So remember, when you're feeling very small and insecure,
      How amazingly unlikely is your birth,
      And pray that there's intelligent life somewhere up in space,
      'Cause there's bugger all down here on Earth.

      --
      "Lack of speed can be overcome. In the worst case by patience." --Znork
    5. Re:Doesn't need to be a spaceship by Ioldanach · · Score: 3, Interesting

      If you were to simply remove yourself from the flow of time for a moment, the rest of the universe would keep chugging along. It would leave you behind. The Earth would spin away from you, as well as orbit away from you. When you re-entered the flow of time you'd be in a different place than where you started from.

      That depends a bit on how you remove yourself from the flow of time. First, there's how you stay in one place, and that's only half the problem.

      If you cause all atoms, down to the smallest level, within the envelope of your craft to be trapped in a void that stops experiencing the timestream and doesn't appear to the outside world, but the void itself is still acted upon by the forces of the outside world, then the void should remain in place until the occupants exit at the designated "arrival" time. The downside to this is that the void should be easily detectable, since you're not jumping through space, you're simply pausing your experience of existence until you want to be un-paused.

      Or, as with the latter, the void can be locked to the reference point without actually being interacted with, this would have the same result without being detectable.

      Then again, maybe the craft would be detectable, but only if you knew to look for it and happened to look in just the right spot while it was sitting there, just out of visible space, perhaps creating a gravity and energy signature as if it were dark matter.

      The third method would be to calculate the exact position of the craft based on the earth moving through space at a perfectly predictable rate and somehow teleport (portal, wormhole, stargate, whatever) from your starting point and time to your end point and time. Obviously, if this were the method employed, interplanetary travel would instantly become trivial as a side effect of time travel. (Pern, anyone?)

      I think the middle method is what's implied in the movies, but I'm not sure how you'd get the void to follow the reference frame without being detectable.

      The second half is traveling backward through time as well as forward. With the third method, above, this is part of the same operation, the teleportation method's destination coordinates simply include a time component. (Ok, "simply" is a stretch, but...) For the first two methods, creating a forward moving void is, well, "relatively" trivial compared to causing the void to experience the timestream backwards, and still be locked in the backwards-moving reference.

    6. Re:Doesn't need to be a spaceship by Scrameustache · · Score: 3, Insightful

      Do we need special "time ships" to travel through space ?

      You do if you expect to be at the same point in time when you get to your space destination.

      you don't need "space ships" to travel through time.

      As long as you don't expect to be at the same point in space when you reach your time destination.

      --

      You can't take the sky from me...

  4. stasis field food storage by frovingslosh · · Score: 4, Funny

    This explains the problem that I have trying to use a stasis field in place of a refrigerator. Every time that I shut down the field the food comes flying out of it real fast! (but fresh)

    --
    I'm an American. I love this country and the freedoms that we used to have.
    1. Re:stasis field food storage by Bogtha · · Score: 4, Interesting

      Coincidentally, the first draft for Back to the Future had a fridge for the time machine, but that was changed because the director thought it would end up with kids watching the film, playing around climbing into fridges, and getting trapped.

      --
      Bogtha Bogtha Bogtha
    2. Re:stasis field food storage by blueZ3 · · Score: 4, Funny

      Reminds me of my favorite children's book (that didn't make it): The Magical World Inside the Abandoned Refrigerator.

      Of course I also liked:

      Eggs, Toilet Paper, and Your School
      Microwaves and Hamsters: An I Can Do It! Book
      Daddy Drinks Because You Cry
      Curious George and the Electric Fence

      --
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    3. Re:stasis field food storage by Bogtha · · Score: 4, Informative

      I spent 60 seconds on Google and found the draft. Next time don't be so lazy.

      --
      Bogtha Bogtha Bogtha
    4. Re:stasis field food storage by kre.86 · · Score: 3, Funny

      not to mention the technical problems involved with trying to a get a fridge up to 88mph

  5. Boiling It Down by eldavojohn · · Score: 3, Interesting

    First off, there are WAY too many pages to this article for me to read but it looks fun so maybe later.

    But in regards to this, I would like a physicist to boil large problems down to "We can't do X because of the simple problem of Y." Example with Mr. Fusion: We can't do Mr. Fusion because the amount of energy that goes into creating the conditions for fusion outweigh the amount of energy produced. That's something measurable and approachable to me, a starting point.

    If it comes down to the problem requiring a Free Lunch, I'd probably give up early--I'm not one to disobey the laws of thermodynamics.

    In middle school I devoted large amounts of time and reams of paper to developing a formula f(n) to produce the nth prime number (at the time I was searching for O(1) oh how naive I was about mathematical induction!) and it was all because a teacher explained how powerful such a formula would be for encryption and many other things.

    While I (obviously) never solved it, I sure the hell enjoyed the simplified form of a much more complex problem. And on top of that, it kind of set the tone for computer science in my life. Could hoverboards & time machines turn a movie goer into a physicist? Maybe not often but it happens.

    --
    My work here is dung.
    1. Re:Boiling It Down by thedonger · · Score: 4, Interesting

      I spent some time in high school looking for a common form of a 2-digit multiplication trick and wound up deriving the quadratic formula. No one was impressed. So much for public school...

      But back on topic, I think Homer Simpson's time traveling toaster is accurate with regards to the time portion: anything you do while in the past creates an alternate time stream only into which you may move forward. The problem the Simpson's didn't deal with is that if you exist in that new future, you will be a duplicate if you are able to travel forward in time to when you are alive. But I don't think forward time travel is possible since there is not/will not be a future.

      Physical position notwithstanding, BTTF - while fun to watch - can't happen. Once you move backward through time you are screwed.

      --
      Help fight poverty: Punch a poor person.
  6. Extra Dimensions by awitod · · Score: 5, Funny

    What you fail to grasp is that the 7th dimension works like quantum sticky tape to hold you in place relative to the things around you as you travel through time. So, you don't really need a space ship because of the relativistic affects of the items around you relative to each other pulling you along. Plus there's the whole inertia thing which requires you to go 88 miles an hour exactly so you always wind up where you started whether you go forward or backward. Try it yourself by drawing two 8's. On is for space space and the other one is for time space.

    Also, don't forget that the velocity has to be in miles per hour, because the metric system is gay.

    DUH!

  7. DeLorian problems by EmbeddedJanitor · · Score: 5, Funny

    The fire was probably due to a well known fact that DeLorians leaked fuel and oil badly. That's why they quit making them.

    --
    Engineering is the art of compromise.
    1. Re:DeLorian problems by Anonymous Coward · · Score: 5, Funny

      The fire was probably due to a well known fact that DeLorians leaked fuel and oil badly. That's why they quit making them.

      Why don't the British make computers?

      Because they haven't figured out how to make them leak oil yet.

      I'm sure you'll get a set of complimentary tightening wrenches with them when they do though.

    2. Re:DeLorian problems by confused+one · · Score: 4, Informative

      Actually, you can still buy them, new. DeLorian may have gone out of business but another guy bought all the parts and manufacturing equipment. He repairs existing ones and will build you a brand new one if you have enough money.

    3. Re:DeLorian problems by yabos · · Score: 3, Funny

      bollocks

    4. Re:DeLorian problems by Mister_Stoopid · · Score: 5, Funny

      I think that, if I had a time machine, I could come up with a more lucrative business plan than smuggling drugs.

  8. Re:cosines by Samschnooks · · Score: 3, Funny

    Um, you really don't want to go off on a tangent because the mods will mark you off-topic. I can see the sines in your post of that happening.

  9. wear your space suit by v1 · · Score: 5, Interesting

    anyone that has (in the past) managed to create a time travel device and has tried it, probably thought they made a disintegration machine, because anything they sent back or forward in time was never seen again. (or before, I suppose)

    Because a second/minute/year/millenia ago that spot was occupied by empty space. The earth is moving very fast through space.

    I've always used that reason to concede that even if we DO make time travel possible, it will be of little practical value.

    Then there's the other snag of transposition... if you say, send yourself back in time, what happens to that volume of space where you arrive? Is it destroyed? And what fills in the void where you left? Or one more expected result is it's transposed with your time's space. Thus all time travel is time swapping, something goes forward and something goes back. Now lets say you do make a time travel machine, and test it without considering the earth-travels-through-space issue... that means whatever you send out, you get a big ball of vacuum back. If it's a very brief travel, you may get a chunk of earth, high pressure ocean, or more likely, high pressure magma. Ouch... hope you got insurance. That'll turn your lab into a disaster area real quick.

    There are so man "problems" with time travel, that it really doesn't matter if its possible or not. It's not useful.

    --
    I work for the Department of Redundancy Department.
    1. Re:wear your space suit by gardyloo · · Score: 3, Insightful

      Because a second/minute/year/millenia ago that spot was occupied by empty space. The earth is moving very fast through space.

      You're assuming some immutable aether to give an absolute reference. Why assume that the place the object might appear later in time is some position stationary with respect to Sol, but not to the galaxy? Or the parent supercluster? Or some other object? We've abolished the Machian idea of an absolute reference frame by now.

  10. "Law of Cosines" ... by Sebastopol · · Score: 5, Insightful

    as serious math?

    Did a communications major write this?

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  11. erm, by Speare · · Score: 4, Interesting

    Reference frames don't travel with respect to themselves. By definition.

    However, you could say that we're that much closer/farther from Vega, or in a different season in our Solar orbit, or in a different timezone, etc. Or the Earth's core has counterspun in relation to its own crust. Or tectonic shifts have occurred.

    Just assume the car is locked onto a specific reference frame, such as a given latitude/longitude relative to the Earth's axis of rotation and the nearest large mass: the Earth's crust under the car. And pass the popcorn, it's a movie for chri'sakes.

    --
    [ .sig file not found ]
  12. Reference frames are relative by omnilynx · · Score: 5, Insightful

    But how far has this reference frame itself traveled during that one minute?'

    Relative to what? Relative to itself, it hasn't traveled at all. And since we don't know the mechanism for time travel, there's no reason to use any other reference frame. Really, until we understand how they are supposed to travel through time we can't discuss the interactions of reference frames across time skips.

    --
    ceci n'est pas une .sig
  13. Aether Drag by argent · · Score: 3, Funny

    Since Professor Brown is obviously using Steampunk technology (look at the ending to the final BTTF), it seems clear to me that the solution to this problem is that the Time Machine is carried along in the Earth's "Aether Drag", the distorting effect that any large mass has on the Luminiferous Aether!

  14. Re:1.21 Jigawatts by Drakkenmensch · · Score: 5, Funny

    1.21 Jigawatts: the energy output of a man dancing a 1.21 minute jig. So next time you jig, be very careful to dance either more or less than 1.21 minute, lest you suddenly go back in time to the 1950s where your dad is a spineless wimp.

  15. Re:Gee.. seems I need a ... by BobSixtyFour · · Score: 3, Funny

    Wrong, as you can CLEARLY see, his server doesn't have the 1.21 Jigawatts necessary to jump OVER the slashdot effect and into your browser.

  16. link by confused+one · · Score: 3, Informative

    here's the link I forgot...

    http://www.delorean.com/

    1. Re:link by veganboyjosh · · Score: 5, Funny

      I don't see the option for the flux capacitor. Link for that?

  17. Did the author not watch the movie? by actionbastard · · Score: 3, Informative

    Professor Brown explained that Einstein simply 'skipped' over that minute and arrived in the same place at a different time. The DeLorean -and hence Einstein- still had their combined velocities of the reference plane (place) that it had when it did the 'timeskip'; that's why it was still going eighty-eight MPH when it reappeared one minute later. If the combined velocities of the 'time traveler' or the 'place' do not change during his trip, then he simply arrives in the same 'place' just at a different time. However, if the 'place' from which he leaves encounters a sudden change of velocity at the exact moment of departure, then he could return in a very different 'place' upon arrival.

    --
    Sig this!
  18. I call AC by frovingslosh · · Score: 3, Insightful

    I call AC. ACs don't get to call BS.

    --
    I'm an American. I love this country and the freedoms that we used to have.
  19. Don't ask me! by mangu · · Score: 5, Funny

    Ask this guy instead.