3 ms·
> Also, why would space limit itself to only expanding outside a physical body? It doesn't, it's just that the forces within the body (the spring in the analog
by SAI_Peregrinus 7y ago
> Also, why would space limit itself to only expanding outside a physical body?
It doesn't, it's just that the forces within the body (the spring in the analogy) are stronger than the expansion.
The "relative to space" bit is the nonsense part of their analogy, but I'm not sure of a clearer way to describe things than what they did. It's not my field.
- Certhas 7y agoMaybe a better way to phrase it would have been moving over the rubber/space? Or through the rubber/space? It really is motion relative to the underlying manifold though. Let's say there was such a thing as a gravitational soliton, that is, a stable ripple in spacetime, then if you are on the same spot as this wrinkle as expansion starts you will move away from it. You move relative to a structure made from spacetime. This was my field for many years. :-) The mathematically precise statement is that you are not moving on a geodesic. You are therefore experiencing acceleration (the objects that are not bound and have increasing distance are on geodesics and do not experience acceleration).