I apologize but it's time for a physics lecture on what an "ideal black body is". It's not Halley Barry.

An ideal black body has perfect emissivity. (Fancy words eh?)
It means the black felt will dump its heat fast. It gets cold then frost or dew happens.
Black felt is a great example of a nearly ideal black body.
To prove I'm not just making shit up (again) I got out a very heavy book that I carried many miles up hill both ways thru a blizzard to Parkland College.
For
The
Science!
Study that picture with the arrows like a star.
There is another image like that that's drawn like a keyhole. Imagine light can go in but not escape and that's how an ideal black body works. The cooling off part? Nobody drew a picture so make your own up.

It works both ways. This FACT is why you don't see a lot of black kids at the swimming pool..
