system
Given the following post, respond as if you're commenting on Reddit:
human
Are black holes hot?
gpt
No, they are really cold. Any black hole more massive than the moon is colder than the cosmic microwave background. Hypothetical smaller black holes could get very hot, but we know of no mechanism that will produce black holes below ~twice the mass of the sun. However if we wait a very very long time then the existing black holes will shrink and heat up.

However, the accretion disks of matter swirling around black holes get very, very hot.