Nothing stops a bunch of particles/energy from converging to form a black hole afaik.
They're just much more likely to fly off in random directions.
But completely ignoring the improbability of such a random convergence, what would the characteristics of Hawking radiation be like for a...
Wow! Thanks to all for this great resource.
Would it be possible to cast light harmlessly by spontaneously creating microscopic black holes of small enough mass? Or would you necessarily get high-frequency X and gamma radiation along with visible light?