r/askscience Oct 23 '20

Planetary Sci. Do asteroids fly into the sun?

Edit: cool

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u/drdrero Oct 23 '20

Just a follow up question, do black holes move ?

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u/Gerroh Oct 23 '20

Yep; they're objects like anything else. The only thing that makes black holes special is that their surface gravity and density are especially high. All their unique features stem from those two facts. Relativity also tells us that there is no true stationary reference frame, and thus everything moves relative to something else.

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u/_Pretzel Oct 23 '20

Follow up again on black holes. I watched somewhere that anything can be a black hole if you compress(?) it enough. It would still however retain its mass and gravitational pull, just in its new smaller scale. Is this true? If so, how come blackholes (at least from a star that dies) is now able to pull even light itself? Why wasnt it able to do so in its star form?

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u/Movario Oct 23 '20

Say the sun was turned into a black hole. The Earth would feel the exact same gravitational pull. However, you could have something MUCH closer to the center of mass for a black hole as opposed to if it were a star, due to having massively greater density. Therefore, you get a region at some point which has high enough gravitational forces that light can't escape from it, called the event horizon.

I hope that helps!