• polycrome@lemmy.world
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    3 days ago

    One way to resolve this is to have some kind of multiverse theory where you don’t travel back in time to your universe, but to a narrow slection of parallel universes that are also shifted slightly so that it spits you out in an analogous location to your initial departure.

  • stebo@lemmy.dbzer0.com
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    3 days ago

    Position isn’t absolute so if this happens this means you knowingly made the time machine memorize position relative to e.g. the sun rather than the earth.

    • klay@lemm.ee
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      3 days ago

      incorrect, that is not what this means. They could have forgotten about the position setting all together. Also why the suns position? it is also moving and non absolute, just like earths. Makes no difference in this meme

      • 1rre@discuss.tchncs.de
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        3 days ago

        All of space is moving, you need to fix a reference point, there’s nothing to stop you making it earth

      • stebo@lemmy.dbzer0.com
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        3 days ago

        They could have forgotten about the position setting all together.

        You’re assuming that the time machine would just change the time and keep the position but there is no absolute reference frame, so the time machine should use some reference frame in which it keeps the position constant. It would then be common sense to have the time machine keep the position relative to the earth. Anything else would be pretty dumb, unless you want to use your time machine also for space travel to other planets.

        why the suns position

        That was just an example. It’s either the sun or the center of our galaxy, or some other reference point so if it wasn’t the earth then the sun is the next most logical option.

  • OddButNotReally@lemmy.world
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    3 days ago

    I remember reading about this concept as a kid in a short story Neal Shusterman wrote called Same Time, Next Year. Blew my mind

  • surph_ninja@lemmy.world
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    3 days ago

    If space is always expanding, I’d really like to know if a time traveler would experience issues existing in a universe where the space between atoms is different from the one they left.

  • Malle_Yeno@pawb.social
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    3 days ago

    It should be illegal to remind people (me, particularly) about Steins;Gate while they’re at work

    I can’t be fucking crying on the clock, dawg

  • Jimius@lemmy.ml
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    3 days ago

    Also, the earth will never be in the same place twice. So it’s not even like you can only jump increments of a solar year.

    • lucullus@discuss.tchncs.de
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      3 days ago

      And its not like there even is a same place. Position is relative, but to what in this case? Doesn’t even make sense

        • OBJECTION!@lemmy.ml
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          3 days ago

          Imagine the universe as the surface of a balloon. The Big Bang Theory stipulates that at one point, the balloon was extremely small, like a single point. But now that the balloon is bigger, you can’t find a particular spot on the balloon where that point was, because everywhere was that point. No matter where you are in the universe, if you turned back time and shrunk the balloon back down, you would be at the point of the Big Bang. Nowhere is closer or farther away from it.

          • funkless_eck@sh.itjust.works
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            3 days ago

            would not the fact that blue shifted galaxies being rare, mean that in general all galaxies are red shifted from the perspective of all galaxies, thus they are expanding away from a point on a similar vector, and thus have a central point?

            And a balloon does have a vector of direction: the mouth piece

            • OBJECTION!@lemmy.ml
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              3 days ago

              would not the fact that blue shifted galaxies being rare, mean that in general all galaxies are red shifted from the perspective of all galaxies, thus they are expanding away from a point on a similar vector, and thus have a central point?

              No, it means the opposite. They are expanding away from all points, because space itself is expanding. In fact, stars are able to move away from each other faster than the speed of light, which is only possible because space is expanding. Again, like the surface of a balloon, we can imagine that the further away two points are from each other, the faster they’ll move away from each other as the balloon expands, so even if there’s a certain maximum speed that you can move along the surface of the balloon, if two points are far enough away from each other the rate that distance is created between them can exceed that speed.

              If there was a single, specific point in space where all the stuff came from, then we wouldn’t observe the same thing in every direction. Sure, we might see stuff ahead of us redshifted because it’s moving faster and stuff behind us redshifted because we’re moving faster, but we should also expect to see stuff to the sides moving alongside us at similar speeds that would not be redshifted. The fact that there’s consistent red shifting in every direction, getting more pronounced the greater the distance, leads us to the conclusion that space is expanding.

              And a balloon does have a vector of direction: the mouth piece

              It’s an analogy, don’t take it too literally.

    • potoo22@programming.dev
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      4 days ago

      There’s a ton of issues with time travel. That could be one, but most fictional time-travel devices can be said to accommodate for the difference in distance. It would just be boring to explain on-screen.

    • TachyonTele@lemm.ee
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      4 days ago

      It could be explained as a time and space machine but just saying time machine is easier.

      That’s how ive always thought of these things in my head.

      • Fushuan [he/him]@lemm.ee
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        3 days ago

        but imagine if you could set it to the same time but different distance, it would allow you to teleport, that might be too strong.

    • Codeviper828@lemmus.org
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      7 hours ago

      At least in Doctor Who, the T.A.R.D.I.S. can teleport through space as well as through time, solving that problem. But most time machines don’t