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Time "travel" is a crazy thing

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  • JacqueChoi
  • Wells
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    Wells polycounter lvl 18
    this is another great time-travel movie.

    i really like how they handled going back in time and affecting the past

    timecrimes_dvd_art.jpg
  • Overlord
    Neox wrote: »
    its even creepier! the earth rotates around the sun with 29.8 km/s, the solar system the galaxy we are in have their own speed - you could land right in the middle of nowhere, woukdn't do that without a spaceship! XD

    I think that wouldn't happen though, because you are also revolving around the earth, which revolves around the Sun, and all of that is revolving around a super-massive singularity. When you time travel , you are actually still in motion when you start. However, it would then be logical to assume that your velocity would become linear rather than angular at your destination. Assuming that you are no longer influenced by gravity and inertia from the motion of the Earth, you would fly away with a linear velocity from your starting point. Or, if you are still influenced by the angular velocity of the Earth, then you would remain in the same position relative to the Earth, but in a differing point in time.

    Clearly, such a method of time travel would be very difficult to accomplish. Instead, of a time machine that travels with you or one that sends you to a point in time without traveling the the points in between, you build a time machine that exists in an unchanging position relative to the Earth. Thus, in order to travel through time, the object facilitating your transport would have to maintain it's relative position and duration with the Earth. In other words, the device would warp spacetime in order to cause the traveler to move through time at a rate differing than that of everything around it. Since the object maintains its position relative to the Earth, no matter what point in time you travel to, as long as the object remains in the same place relative to Earth, you will always find yourself in the same relative position after reaching the desired point in time. Again, I'm speculating based on what little I know.
  • crazyfool
  • skylebones
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    skylebones polycounter lvl 10
    When you turn thirty years old and teleport thirty light years away with a super telescope in tow, then turn around and look back at earth, would you see your self being conceived?

    Maybe instead of time machines we should be working on better telescopes and teleportation.
  • dfacto
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    dfacto polycounter lvl 18
    Overlord wrote: »
    I think that wouldn't happen though, because etc etc

    Valid, but there are also options where some form of hyperspace/subspace comes into play, and then you could potentially remove that factor depending on what the interface between dimensions is like.
  • Japhir
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    Japhir polycounter lvl 16
    This is a really interesting thread :).
  • Overlord
    dfacto wrote: »
    Valid, but there are also options where some form of hyperspace/subspace comes into play, and then you could potentially remove that factor depending on what the interface between dimensions is like.

    Well, then you get into the realm of quantum tunneling (a.k.a. wormholes). But that would give you the ability to not only time travel, but also travel through space. You just have to find a valid path that leads you to both the desired space and time coordinates.
  • Mrskullface
    I thought about that. If things get slower as it goes faster and things can't ever reach the speed of light due to the fact that there is not enough energy in the universe to propel something that fast,WHAT IF you could reach the speed of light would time stop? and if you go faster would time start to go backwards. Maybe when you approach the speed of light you just stop instead of turning into light? gnaw mean?
  • Overlord
    I thought about that. If things get slower as it goes faster and things can't ever reach the speed of light due to the fact that there is not enough energy in the universe to propel something that fast,WHAT IF you could reach the speed of light would time stop? and if you go faster would time start to go backwards. Maybe when you approach the speed of light you just stop instead of turning into light? gnaw mean?

    Light can travel as fast as it does because it has no mass. Anything with mass warps space as it accelerates, thus requiring more energy to continue to accelerate. Space actually expands and contracts depending on your speed relative to the speed of light. It isn't that there isn't enough energy to accelerate to the speed of light, it's that the energy requirements increase exponentially to the point that it requires an infinite amount of energy to get to 100% of light speed.

    However, there are ways around that limitation. Warping the space behind and in front of an object will propel it forward without applying any inertial force, which would allow the object to travel at speeds in excess of light speed. This will not, however, cause any change in time because time will pass the same as if you were standing still since you're not moving relative to normal space. Such a phenomena would require immense amounts of energy to manipulate space in such a manner, but less than it would take to accelerate to 100% of light speed. It's doable, but very very hard to do.
  • Steppenwolf
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    Steppenwolf polycounter lvl 15
    I don't think time travel as depicted in scifi and movies makes any sense. Time isn't evenly distrubuted through the universe due to the gravitation. Right now if you sit straight in front of your PC your head exists in a different time as your feet.
    So i think that different times exist simultanously as different coordinates in the fabric of our universe. Suppose you could somehow travel to what for us was the year 1945 or whatever you wouldn't actualy find Earth there but maybe some other coordinate in the universe that has moved into this place since. Not even talking about some grazy extradimensional stuff here. Just the regular universe that you can see when you look out to the night sky. Just wrap your head around the fact that the stars on the sky are extremely far away and what you see isn't what happens there right now in real time.
  • Taz
  • dpaynter26
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    dpaynter26 polycounter lvl 11
  • xvampire
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    xvampire polycounter lvl 14
    [ame="http://www.youtube.com/watch?v=DEfC4y8KT3E"]Time Commando track 1 - YouTube[/ame] only one person I can trust for time travel
  • vreza
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    vreza polycounter lvl 12
    I always see time travel just like Windows system restore. U cant go back to a specific time unless there a restore point. So one can only travel back in time as far as the date of earliest invented time machine. So is time machine essentially a big recording machine that records everything?
  • Compo
    skylebones wrote: »
    When you turn thirty years old and teleport thirty light years away with a super telescope in tow, then turn around and look back at earth, would you see your self being conceived?

    Maybe instead of time machines we should be working on better telescopes and teleportation.

    You would yes, same idea that most all Hubble pictures are of the past events because of the time needed for the light to reach us. Star explosion 30 ly away happened 30 years ago (by the time we see it).
  • dpaynter26
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    dpaynter26 polycounter lvl 11
    So we can see into the past ;) LOL
  • eld
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    eld polycounter lvl 18
    skylebones wrote: »
    When you turn thirty years old and teleport thirty light years away with a super telescope in tow, then turn around and look back at earth, would you see your self being conceived?

    Maybe instead of time machines we should be working on better telescopes and teleportation.

    If the light never reached space, or in the case if most likely being born in a hospital, it would've been dispersed and turned into different kinds of radiation, you'll never be able to see your own birth unless the light from your birth is still intact.

    But yes, we're currently able to see as far back in time as the universe has existed, due to no light having actually existed before that time, we can't see any further.

    observable_universe.jpeg
  • rooster
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    rooster mod
    eld wrote: »
    But yes, we're currently able to see as far back in time as the universe has existed, due to no light having actually existed before that time, we can't see any further.

    isn't that slightly untrue, because there are galaxies where the speed we're moving apart is greater than the speed of light- so we'll never be able to see them? (that's kind of a question, I thought I remember reading something to this effect)
  • eld
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    eld polycounter lvl 18
    rooster wrote: »
    isn't that slightly untrue, because there are galaxies where the speed we're moving apart is greater than the speed of light- so we'll never be able to see them? (that's kind of a question, I thought I remember reading something to this effect)

    Speed of light is constant, if it shoots out from a galaxy moving away from us at great speed it will not move at (the speed of light - the speed of that galaxy), it will maintain its constant speed.

    It will eventually reach us as nothing with matter can move at the speed of light, even if the space between two galaxies expands at a speed greater than that of the speed of light.

    This happens with light when something moves away from you, speed of light is the same, it just gets stretched out.

    Blue-Shift-and-Red-Shift..png

    My point on the observeable universe is that if we look at a patch of sky and try to look as far away as we could, light would've had to travel for such a long time to reach us that it would've had to been longer than the existance of the universe, and since no light existed back then, we can't see what is there even though there is stuff there, since that light has not reached us yet.

    When we look at the sky we see the past, and the further out you look, the further back in time.
    We're in our lifetime unable to see past our observable universe.
  • rooster
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    rooster mod
    light speed may be a constant but it's the space itself the light is in that is expanding, causing two points in space to move away from each other faster than the speed of light.

    according to this article: http://curious.astro.cornell.edu/question.php?number=575
    "As a consequence of their great speeds, these galaxies will likely not be visible to us forever; some of them are right now emitting their last bit of light that will ever be able to make it all the way across space and reach us (billions of years from now). After that, we will observe them to freeze and fade, never to be heard from again"

    I do follow what you're saying about the observable universe, just interested about how expansion affects things (not really in our lifetime, natch)
  • eld
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    eld polycounter lvl 18
    You got me there, the expansion of spacetime means more length for constant light to travel :P
  • Overlord
    The more I learn about physics and the universe, the more I feel like we are all simulations running inside of a bigger simulation. So that begs the question, is there a "real" world outside of this simulation? The whole idea just creeps me out.
  • dfacto
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    dfacto polycounter lvl 18
    Doesn't really matter unless someone pushes the reset button. Really the only truly troublesome concept is that free will might be an illusion and we're pretty much in a rail-shooter. Quantum physics seems to provide for random events, but that might itself have a deeper rule-set that we don't know about.
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