[morebortplates]

What's "inside" of a black hole, meaning behind the event horizon is forever causally cut off from our universe. The Hawking radiation comes from the space around the event horizon. In theory black holes can become very hot if their mass is small. This happens at the end of their life which is in the order of 10^80 years for stellar black holes.

Here is a calculator to play with some values. https://www.vttoth.com/CMS/physics-notes/311-hawking-radiati...

[jfengel]

Note that this evaporation time assumes a universe at absolute zero. That 10^80 years can't even begin until the CMBR cools enough, perhaps 10^40 years.

Admittedly that's an eyeblink compared to the evaporation time scale, but it does mean that we won't observe any evaporation until many orders of magnitude longer than the universe has existed.

[db48x]

Or unless you manufacture or discover a low–mass black hole

[jfengel]

That's right. If we could create one in a supercollider, it would would be so small that it would be hot enough to evaporate instantly.

There might also be a range of primordial black holes formed directly out of pre-CMBR energy. They'd have to be small enough to be hotter than the CMBR, but not so hot that they'd already have evaporated in the last 14 billion years. That's a relatively narrow range, all things considered, but if primordial black holes exist at all then they could exist at any range.