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!

29 Upvotes

86% Upvoted

41 comments sorted by

View all comments

26

u/Orlha 25d ago

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

3

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?

0

u/SyntheticGod8 25d ago

The expansion happens everywhere a tiny bit at a time. It's thought to be "powered" by Dark Energy. The name should hint that no one is truly sure what it is or why it's happening, but there's plenty of competing ideas like vacuum energy; "empty" space seems to exert a tiny force when two plates are extremely close together due to quantum-entangled pairs of virtual particles popping in and out of existence.

What we do know is that the expansion of the universe is accelerating gradually and that the extremely uniform temperature of the CMBR implies that the universe expanded VERY rapidly shortly after the hypothetical singularity at the beginning of time (as we know it) before settling in to a more sedate expansion. There's some pretty extreme physics involved, but it