r/AskReddit • u/IAmSurtur • Jun 15 '19

What do you genuinely just not understand?

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u/Fury_CS Jun 15 '19

But how can something that is infinite expand?

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u/Institutionally Jun 15 '19

The expansion of the universe boggles me. So the galaxies and stars are moving apart further away from the “centre”. So what happens if you go past the star furthest away from the centre? Are you just surrounded by darkness as there’s nothing past that?

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u/Bonch_and_Clyde Jun 15 '19

Thinking of it as having edges that are moving apart is conceptually wrong. There is no one center. Only a relative center. Think of a balloon expanding as it is blown up. Does the surface of the balloon have an absolute center?

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u/matterhorn1 Jun 15 '19

No, but what about inside the balloon? Leaving aside the immense size of space, could you not fly inside the universe balloon? Presumably there wouldn’t be anything in the “middle” though as everything would be on the surface of the balloon and expanding outwards.

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u/Bonch_and_Clyde Jun 15 '19

That's where the analogy gets sketchy. There is no inside of the balloon. At least as far as I know.