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Can someone ELI5 why the rate of expansion of the universe has to be a constant everywhere? Couldn't different parts of the universe be expanding at different r
by yosito 9y ago
Can someone ELI5 why the rate of expansion of the universe has to be a constant everywhere? Couldn't different parts of the universe be expanding at different rates? And couldn't that rate change over time?
- danharaj 9y agoIf that's true then it needs to be explained, i.e. new physics. General Relativity affords uniform expansion through the cosmological constant. Non-uniform expansion means new fields, so either dark matter or modified gravity.
- deleted 9y ago[deleted]
- philipov 9y agoThis idea is known as Eternal Inflation. Here is the first in a series of 4 lectures about it: https://www.youtube.com/watch?v=xUZeZD9sytc https://www.youtube.com/watch?v=xUZeZD9sytc The main problem with eternal inflation is it gets us attempting to make statements about regions outside what we can observe directly.