# Can a black hole bounce?

Is there a limit to the amount of matter that a black hole can accrete per second and if so could a certain sized black hole bounce off a dense enough surface?

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Look, there's no limit to the accretion because the blackhole simply starts growing as it accretes more mass. I don't think it can "bounce off" any surface.

Yes, if the gravitational forces are comparable, for example, if it encounters another black-hole, they can get in equilibrium, bounce off each other or simply merge.

This happens in the universe.

Every galaxy is found to have a supermassive black-hole at the center. We have evidence for galaxies merging along with their black-holes. Sometimes the galaxies just tear each other apart from tidal influence and the black-holes simply don't interact.

Although, I have never heard of anything like bouncing or merging happening on garden-variety black-holes. The truth is, we haven't detected any significant sum of black-holes. All we have and are sure of are the black-holes at center of galaxies.

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LIGO's main purpose is to look for mergers of stellar-mass black holes. It's an expected event, it just hasn't been observed optically. –  Jerry Schirmer Feb 26 at 23:02
@JerrySchirmer Exactly! –  Cheeku Feb 26 at 23:03
but you can't say that stellar mass black holes are unobserverd. You have plenty of examples of those, such as things like Cygnus X1. –  Jerry Schirmer Feb 26 at 23:07
@JerrySchirmer Yes, I didn't actually mean unobserved. I didn't use 'unobserved'. We have like millions of galaxies to run simulations and do data analysis, but not such a "significant sum(number)" of black-holes. –  Cheeku Feb 26 at 23:11
If you are taking the charged BH scenario, then the important quantity would be the ratio of charge, $q$ to BH mass, $M$. The larger $q/M$ the better the bounce. In fact you could probably calculate a minimum $q$ necessary to get a good bounce by requiring that the electrostatic repulsion is sufficiently great as to force the BH to turn around before it could get close enough to accrete any matter from what it is bouncing off of. –  jeffdk Feb 27 at 10:49