• cynar@lemmy.world
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    1 month ago

    It’s worth noting that spacetime isn’t static. Space “flows” into mass. It’s akin to a treadmill, you need to constantly move “upwards” to stay in place.

    This is also the reason that uniform gravity, and acceleration are identical. With acceleration, the “ground” is constantly moving upwards into new space, pushing you along. With gravity, space is constantly moving down through the floor, trying to push you into the floor. It’s functionally the same thing.

    • ProfessorProteus@lemmy.world
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      1 month ago

      That’s a really interesting perspective. I don’t think I’ve ever seen it described that way before, but it’s very easy for me to grasp. Do you have any resources I can look into for more information? Does that concept have a name I can look up?

      • cynar@lemmy.world
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        1 month ago

        It was the initial description used in my 1st year physics degree course. Not sure if it has an explicit name. We also jumped fairly quickly from there to the maths.

        Basically space time can stretch infinitely, and flows towards mass. Anything on that spacetime is drawn along. It’s functionally identical to a standard force. Straight lines twist into spacetime spirals (aka orbits etc).

        Physics has lots of interesting mental models for different things. Unfortunately, most are flawed, so dont lean on tgem too hard. What actually happens is way beyond what our monkey brains can interpret. The best we can do if follow the maths, and try and fit something to the end result.

        • ProfessorProteus@lemmy.world
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          1 month ago

          Yeah, I’m aware that all or numbers and models are, at best, representative of what is really happening. That’s what I love about the limits of our knowledge: there always something more to learn.

          I wonder how spacetime around a black hole’s ergosphere is represented by the “flow” analogy. Maybe like water swirling around a drain?