Relative space vertigo


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I read Brian Cox and Jeff Forshaw’s Why Does E=MC2 and Why Should We Care a couple of months ago. It’s a great book. The audiobook, especially, is recommended, since Forshaw reads it in a deep Northern English accent. The authors give an overview of the history of physics which, they point out, is necessary to know in order to understand what Einstein was on about when he proposed his famous equation. One thing I was really struck by was their description of the idea (or reality, actually) of relative space.
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(Sorry, if I bungle this up. I’m sure those who know science better than I will correct me if I get some of this wrong.)
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Imagine you go to bed the night of your birthday. One year later, exactly, will you and your bed be in the same exact spot in space? At first, you’d think so, because the earth move around the sun once a year, so it seems quite straight forward that you would be. But while you might be in the same spot relative to the sun, the sun itself is moving through space. So, no, a year later, exactly, you will not be in the same spot. And not only is the sun moving, so is our whole galaxy and the whole of expanding space. We are never in the same spot, ever. And there’s no way of pin pointing where we are, absolutely. The whole thing is in motion and all position is necessarily relative. Happy birthday to you!
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Reading that passage produced an almost existential feeling of vertigo for me.
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I was reminded of that feeling when I watched the timelapse above. It’s one of the best I’ve seen. The way the camera doesn’t sit on the ground providing relative (!) stability, but floats around, just like all of us and all of space, is very evocative of that feeling. We’ve got nothing to hold on to!

  • Timothy V Reeves

    The thing to remember here is that the concept of “location” is, because of our Earthly experience, only meaningful with respect to context (or “Frame of reference” to use a technical term) ; that is, a position can only be defined relative to another position, a position which one assumes to have a distinctiveness by virtue of the presence of material conditions. e.g. You wake up in the morning in the “same place” because “sameness” is defined in relation to the surroundings of your bedroom. From a definitional point of view it’s as simple as that. But once you get into the question how different reference frames relate, that’s when it gets interesting.