this post was submitted on 02 Oct 2023
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Everything not gravitationally bound is moving away from everything else. Every single point in space is growing larger. That means that things farther away from you are moving away from you faster then things closer to you. That's true no matter where in the universe you are.
There's not really an "away" from the big bang. That's something science communicators fail to explain - the big bang happened everywhere. Space may have been infinite in size (we don't know) and it still happened everywhere.
I'd recommend looking up the YouTube channel for FermiLab. They've got some excellent videos on the subject.
Thank you so much for the explanation!
I’m going to sound like a total idiot but if our universe was at the center of a ginormous sphere could that give an illusion that every point in space was moving away from another when in fact we could all be falling (getting pulled by gravity) toward whatever edge of the sphere we are closest to?
Kind of a tangent at this point, but there is a very good reason that that couldn't be the case: according to the shell theorem , nowhere in the interior of a spherical shell of matter experiences any net gravitational force -- wherever you are inside the sphere, the forces counteract exactly.
Otherwise, though, the metric expansion of space is different from typical movement, and it isn't correct to say that things or being pushed or pulled. Rather, the distance between every pair of points in the universe increases over time, with that rate of increase proportional to the points' distance. Importantly, for very distant points, the distance can increse faster than the speed of light, which would be disallowed by any model which describes the expansion in terms of objects moving in a traditional sense.