Minimum size of black hole

What is the minimum size a black hole could be? I have been told that they were worried that the LHC would create a black hole, yet they say the Sun cannot be a black hole. I understand that the black hole may evaporate very quickly, but I still don't understand what the minimum size is.

• Duplicate of How small are the smallest black holes?. – ACuriousMind Apr 10 '15 at 22:10
• @ACuriousMind I disagree. That question asked about stable black holes. This asks about any black hole. – Jimmy360 Apr 10 '15 at 22:12
• @ACuriousMind and Jimmy360 I do mean any black hole. Not just stable black holes. – Benichiwa Apr 10 '15 at 22:18
• It's not that the Sun "cannot" be a black hole, it's that the process that makes a star into a black hole won't work unless there's enough mass. There has to be so much gravity that nothing can stop the collapse. Less mass and something--electron degeneracy pressure for white dwarves, etc--will be able to make it balance. – zeldredge Apr 10 '15 at 22:19
• Then I don't think there is any such limit - in classical GR, if you get the required mass inside the Schwarzschild radius, you get a black hole. In reality, there will probably quantum effects at very small scales making that classical statement invalid, but since we do not have a quantum theory of gravity, there can't be an accepted answer what happens. – ACuriousMind Apr 10 '15 at 22:20

• This scenario (I mean paragraph 2) sounds quite wrong to me. What about Hawking radiation? To get to the moon, travelling at the speed of light, you would have to create black holes of mass $>10^{5}$ kg, since a lower mass black hole would evaporate in a fraction of a second, releasing $\sim 10^{21}$ J during that time. The black holes you are talking about would evaporate in a vanishingly short time. – Rob Jeffries Apr 13 '15 at 22:04