• ripcord@lemmy.world
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    7 months ago

    Not exactly. Things are moving relative to each other, but it really is all relative and local. There’s no central point in the universe that the earth is moving away from. The earth is moving relative to the sun. But relative to you, the earth isn’t moving. Relative to the earth, the sun is moving.

    There’s no reason for her to move away from the earth unless she’s being accelerated by something. It’s not like the earth would zip away because it is moving relative to some distant, arbitrary point and she suddenly becomes “stationary”. There’s no universal “stationary”.

    I guess where it gets messy is that the earth IS being accelerated to some extent by different things (other planets, the moon, etc). I’m not sure how much. So if she didn’t accelerate along with it at all, it would move away from her.

    • oce 🐆@jlai.lu
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      7 months ago

      There’s no reason for her to move away from the earth unless she’s being accelerated by something.

      Isn’t the Earth accelerated by the Sun’s gravity, while she isn’t anymore? If yes, she would keep going straight while Earth keeps following its circular orbit, which is equivalent to her moving away from Earth.

      • Swedneck@discuss.tchncs.de
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        7 months ago

        again, straight compared to what?

        there is no center of the universe, nor a universal grid that things can reference. one of the most fundamental tenets of astrophysics is that everything is relative and statements like “travelling straight” are simply nonsensical unless you specify what it’s travelling straight in relation to.

        • petrol_sniff_king@lemmy.blahaj.zone
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          7 months ago

          The… Earth and Sun.

          Those are the reference frames.

          You start by traveling with the Earth.
          Gravity “turns off” for you.
          The Earth then curves away as it orbits the Sun.

          You just follow the tangent line.

          • oce 🐆@jlai.lu
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            7 months ago

            Yes, that was my point. I think it aligns good enough with the comics.

      • ripcord@lemmy.world
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        7 months ago

        You know…I believe you’re right. If she somehow became totally massless.

        Edit: no, as other people pointed out it doesn’t make any sense that she wouldn’t be “affected” by gravity even with no mass.

        • oce 🐆@jlai.lu
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          7 months ago

          Edit: no, as other people pointed out it doesn’t make any sense that she wouldn’t be “affected” by gravity even with no mass.

          That’s the assumption in my comment: “while she isn’t anymore” accelerated by gravity. I think that’s what we could infer from the trajectory on the comics.

    • Anafabula@discuss.tchncs.de
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      7 months ago

      If she is still affected by gravity, but passes through matter, she would immedietly fall through the floor and start orbiting the earth through the planet.

      Without gravity she would no longer follow the earth’s/sun’s/etc. orbit.

      • Swedneck@discuss.tchncs.de
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        7 months ago

        but the question is what would determine the trajectory then, there is no universal arbitrary straight line, that’s a concept that just doesn’t make sense under physics as we know it.

        Even massless particles gain an effective mass and thus interact with gravity/spacetime; according to everything we’ve observed and calculated so far the only sensible result is acting like light does, and weakly interacting with gravity.

        • Anafabula@discuss.tchncs.de
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          7 months ago

          Well, yea, idk how moving through spacetime without following it’s curvature would makes any sense. Which is what gravity is. Meaning the comic makes no sense.