4 ms·
Not quite, expansion doesn't happen on such small scales. Expansion is a property of the Friedman-Lemaitre-Robertson-Walker metric, which is a solution to the
by mr_mitm 5y ago
Not quite, expansion doesn't happen on such small scales.
Expansion is a property of the Friedman-Lemaitre-Robertson-Walker metric, which is a solution to the Einstein equations if you assume everything is isotropic and homogeneous. Spacetime around a star or a galaxy is obviously not homogeneous. It looks much more like a Schwarzschild metric, which features no expansion.
It may help to think of the universe as a cake with raisins in it. When you bake the cake, the dough expands uniformly, but the raisins do not.
Small caveat: If dark energy has a certain property, it changes things and a "big rip" will occur, tearing apart everything but elementary particles.
- skulk 5y agoIf expansion is indeed happening, wouldn't it play a role everywhere, even if it's eclipsed by whatever else happens to be going on?
- Akronymus 5y agofrom my understanding, it happens at ever scale. But the other forces (weak, strong, gravity, electromagnetism) are MUCH more powerful than that at small scales, and thus not observable at small scales.