# Small black holes

Homework Helper
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## Main Question or Discussion Point

What is the smallest mass required to produce a black hole? I seem to remember that some particles in a high energy accelerator could collide and produce tiny black holes that would then evaporate into Hawking radiation.

Could a mass that is less than the critical mass required to produce a black hole be made into one through some collision or explosive force?

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ranger
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I think those black holes are called micro black holes (where they ever observed?). The smallest mass needed would probably be planck mass.

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Could a mass that is less than the critical mass required to produce a black hole be made into one through some collision or explosive force?
The critical mass is actually defined by the volume into which you enclose it. Therefore, for a given mass you can find a volume for which a black hole will form. That is the idea behind those collision.

This is speculative, it has not actually been observed.

Homework Helper
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I was thinking more along the line of a solar mass of about 13.5 times our sun. If we assume that a mass of 14 times our sun is required for gravity alone to produce a black hole, could an implosive force (shock) compress the sub-black hole mass into a black hole and if so, would the resulting black hole be stable?

I was thinking more along the line of a solar mass of about 13.5 times our sun.
So that is not going to happen in an accelerator :surprised
If we assume that a mass of 14 times our sun is required for gravity alone to produce a black hole, could an implosive force (shock) compress the sub-black hole mass into a black hole and if so, would the resulting black hole be stable?
Technically, no black hole is stable. They evaporate (and we are fairly conviced that this is correct, independently of models, I mean it does not rely on string "theory" or LQG or whatever... the calculations of Hawking are semi-classical QFT in curved space-time).

I must admit that I do not fully understand you concerns :uhh:
Producing micro black-hole at an accelerator simply consists in having a sufficient amount of matter(-energy) in a sufficiently small amount of space(-time). Of course we cannot get up to the Planck mass in accelerators, but this classical value can be lowered if (for instance) there are "large" extradimensions.

A good entry point in the literature is this article on Black Holes at Accelerators