Comment on Time travel doesn't work unless you also have teleportation. If you travel to the past/future, Earth will be in a different position in its orbit, and you'll die in space.

TheLeadenSea@sh.itjust.works ⁨5⁩ ⁨days⁩ ago

• TrickDacy@lemmy.world ⁨4⁩ ⁨days⁩ ago

  Op thinks the universe is built with some inherently absolute positioning method. Thanks for writing this

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• TommySoda@lemmy.world ⁨5⁩ ⁨days⁩ ago

  But if you’re in a moving car and “pop” back a few seconds while the car doesn’t you won’t be in the car anymore. If it worked more like rewinding a video you wouldn’t need to do much, but I’m assuming OP means literally going “poof” and now you’re back in time. If that’s the case, you would still need to know how Earth is moving through spacetime. If you don’t know your relativistic relationship to the Earth and every other object in the universe then how would you know where you are or your own relativity compared to the Earth?

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  • Dave@lemmy.nz ⁨4⁩ ⁨days⁩ ago

    Their point is that (as per relatively), all movement is relative to something. So if the earth moved away then you must be measuring in relation to some other reference point. There is no absolute positioning system. So when you say the earth is moving, what is it moving in relation to? And why did you pick that reference point instead of having a time machine that uses earth itself as a reference point?

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    • TommySoda@lemmy.world ⁨4⁩ ⁨days⁩ ago

      But that’s the thing though. How can you determine the Earth as a reference point without knowing how it relates to other objects in space? “Here” is as useful a coordinated system as a fake absolute positioning system. “Here” is just your relation to other objects. If you don’t know what your relation to those objects is you can’t determine where “here” is, or the Earth for that matter. Whether it’s the machine or the person operating it, something or someone has to calculate where the Earth is in order to use it as a reference point.

      If you are driving away from your friend and 20 mph, from your perspective they are moving away from you at the same speed while you are the one that’s stationary. The only thing determining your location, or reference point, is your relation to each other.

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      • ByteJunk@lemmy.world ⁨4⁩ ⁨days⁩ ago

        You’re still thinking in a context where the earth is travelling around the sun, etc etc.

        If you assume the Earth as the reference point, then that is fixed, absolutely frozen, doesn’t move at all. That’s point zero.

        You cannot calculate where the earth is. What you do is calculate where everything else, the universe itself and even other dimensions, are with regards to your fixed point.

        This can feel counterintuitive, but here’s a random visualization: youtube.com/shorts/UZyuZVvCE78

        Note that, in that video, only the perspective has changed. The solar system is moving as usual.

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  • 7uWqKj@lemmy.world ⁨4⁩ ⁨days⁩ ago

    Exactly, and due to earth’s rotation you don’t even need the car.

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• half_built_pyramids@lemmy.world ⁨4⁩ ⁨days⁩ ago

  Use the time and space machine on a ruler and send it back in time a pico second, then a millisecond, then a thousand, then a second, then a minute. You just have to calibrate with measurements first.

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• fubbernuckin@lemmy.dbzer0.com ⁨4⁩ ⁨days⁩ ago

  I’m using the microwave background as a reference

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  • daniskarma@lemmy.dbzer0.com ⁨4⁩ ⁨days⁩ ago

    I tried, but then it started blinking.

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  • kryptonianCodeMonkey@lemmy.world ⁨4⁩ ⁨days⁩ ago

    The microwave background is like a rainbow. When you move, it appears to move. You’re always at the “center” of it.

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    • fubbernuckin@lemmy.dbzer0.com ⁨4⁩ ⁨days⁩ ago

      You can measure the Doppler shift relative to the cosmic microwave background though

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  • TheLeadenSea@sh.itjust.works ⁨4⁩ ⁨days⁩ ago

    Lol, that’s omnipresent

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