Dodecahedrus

Dodecahedrus t1_j6xem6y wrote

I saw a question in the last week along the lines of “If the universe is 13 billion years old and expands at the speed of light, then how is it 92 billion lightyears wide?”. (Oversimplified.)

I don’t think I opened it for the answers. Perhaps I should have.

Then today I saw a question here about the speed of differs with light moving through different substances (oversimplified, thread in question is here ).

Could an answer to the first question be that the universe at the moment of the big bang wasn’t a vacuum? Is this related to the undetectable dark matter that is pushed outward with the growth of the universe?

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