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> How small can a black hole be and still qualify as a black hole? There's no theoretical lower bound on the mass of a black hole. Once matter has ceased to re

> How small can a black hole be and still qualify as a black hole? There's no theoretical lower bound on the mass of a black hole. Once matter has ceased to repel other matter, it will continue to fall inward. A violent impact could generate the forces necessary on a small scale to create micro black holes. Black holes do seem to slowly lose energy though, so small ones would not live very long[0]: [0]: https://en.wikipedia.org/wiki/Micro_black_hole#Hawking_radiation https://en.wikipedia.org/wiki/Micro_black_hole#Hawking_radia...

codethief 6y ago
> so small ones would not live very long Actually, this is completely unknown. While Hawking radiation is a well-established effect in the semiclassical limit (read: when gravity is weak), we don't really know what happens when the Schwarzschild radius reaches scales where tidal effects become noticeable already near the event horizon and, eventually, quantum gravitational effects (supposedly) take over. In fact, this whole question lies at the heart of the black hole information paradox. Do black holes evaporate completely? Or will evaporation stop at some point, leaving behind a black hole remnant?
Dylan16807 6y ago
> A violent impact could generate the forces necessary on a small scale to create micro black holes. If there are extra dimensions that make it especially easy to create a black hole. Otherwise, you're looking at a Planck mass of 22 micrograms as a lower bound. It's effectively impossible for a violent impact to cram that much matter/energy into a single subatomic point.