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The universe was always only expanding between galaxies, not within them.
by indoordin0saur 1y ago
The universe was always only expanding between galaxies, not within them.
- Razengan 1y agoSo wait, individual stars aren't getting further apart? Galaxies aren't getting "bigger"/more diffuse?
- kmeisthax 1y agoGalaxies have enough gravity to counteract the expansion of the universe.
- Razengan 1y agoSo do we see the expansion cancelled out by the gravity, or do we only see the gravity? I mean, is it change = gravity or change = expansion - gravity Because this just made me wonder.. is "dark energy" simply the absence of gravity? i.e. just in regions where there is next to no matter/activity?
- JumpCrisscross 1y ago> do we see the expansion cancelled out by the gravity, or do we only see the gravity? We see gravity overpowering expansion. Same way you can’t launch yourself into orbit by throwing lots of pennies at one a second.
- recursivecaveat 1y agoImagine the universe as a giant balloon. Inside are little miniature balloon stars floating around, tied with string into balloon galaxies. If we heat the air: the big balloon expands, the clusters of mini-balloons spread out from the other clusters, but the clusters don't get any more diffuse. The string is way way too strong to be overpowered by the separating force from the expansion of the gas over short distances.
- Razengan 1y agoI mean, this is tricky to even ask: is there still expansion INSIDE galaxies, BUT it's countered by gravity? Or is there no expansion within galaxies at all? i.e. is dark energy or whatever that causes expansion only present in the absence of matter, or is it present everywhere regardless of matter, but because matter also has its own gravity the expansion is not visible/relevant?
- indoordin0saur 1y agoNo, stars stay just as close to each other. Also even the nearest galaxies (Andromeda) are either getting closer or staying at roughly the same distance.