Is it at all possible that instead of being pushed away, we are instead getting pulled toward something huuuuuge via gravity? As if we are falling into something way greater than ourselves? I thought this was a wild idea but after I Googled it I found out that there is such a thing as a “Great Attractor”. Something 150 million light-years away is literally pulling all nearby galaxies towards it but no one knows exactly what it is.
So how do we know there aren’t any other Great Attractors, Greater Attractors, ad infinitum?
Gravity bends light. You can literally detect large masses by how they distort the space around them. From what we can observe, space overall is pretty flat. AND we can measure where stuff is going using various proxies i.e the doppler shift, spectral lines, standard candles etc. If stuff was being pulled toward some mass, its going to cause deviations in how fast things are moving relative to each other. Which in the case of the great attractor, is what is happening. But if you are asking whether everything is falling toward something in every direction equally, the answer is no due to the shell theorm.
What do you mean by that?
Look at a piece of paper. Mark two points on it that are a good distance apart. Travel can only happen along the surface of the paper. When it’s flat, your time of travel depends on the distance between the two points on that paper.
Now dap a spot of glue next to one of the points and fold the paper in such a way that the other point comes to rest close to that glue. Wait for it to bind and then spread the paper a little without breaking the glue. That glued point is a wormhole, a place where two points of that flat 2D universe touch despite not being next to each other. Travel from point A to point B is now a shorter distance thanks to the wormhole. But there is no way in which the paper universe can be described as flat anymore.
Or think of a papermache ball, that’s also made from paper but if you travel long enough in one direction, you’ll end up where you started. Because it isn’t flat.
Now our universe is 3D not 2D, but from a higher dimensional perspective it has the same prooerties of flatness as that 2D paper has for us.