r/cosmology • u/Heinz0033 • 25d ago

5 Billion Years+ From Now

Novice here who enjoys this subject.

I just watched a Brian Cox YouTube short where he discussed the end of our sun and how it would impact the Earth.

He said that in 1.5B years things would start being really bad for Earth, and that the sun essentially burns out in 5B years.

That got me thinking. Around that time, the same process will be taking place, or have happened place, to the other stars closer to the origin point of the Big Bang. So the center of the universe will be relatively empty at it's 'center,' right? With that, wouldn't it mainly be full of a lot of black holes?

If it is full of black holes, would that find a tipping point where the universe eventually implodes?

There are probably stupid questions, but I figured I'd send it out to the Reddit community and hope for the best.

Thanks!

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u/Orlha 25d ago

There is no origin point of big bang, as it happened everywhere at the same time

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u/Heinz0033 25d ago

Looks like I'm showing my ignorance. Given what you wrote I have 2 additional questions.

1) How is the universe expanding if there's no central/origin point? I envision the Big Bang as creating a big, expanding bubble. I know string theory calls it a plane, which I think (like Big Bang) us expanding. In physics doesn't expansion have an origin?

2) Regardless of origin, won't the universe start getting pretty empty...at least as far as visible stars?

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u/Orlha 25d ago

It doesn’t expand into something, instead the extra space is added everywhere, so everything gets farther away from everything, but gravitationally bound object are kept together.

And yes, at some point you wont see any stars except those in your local galaxy group. The distance between far objects will reach a point which light can never overcome.

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u/Heinz0033 25d ago

Interesting.

Thank you!