Turns out artificial intelligence needs a nap every once in a while to stay accurate, and that may tell us something fundamental about our own minds.

We've all had a rough night and woke up even more tired than we went to bed. But if you're in your 60s and that's becoming a common occurrence, it may be a dangerous sign.

Believe it or not, there's a scientific explanation for some of the world's most common and terrifying demons, imps, and ghosts. But it's not very comforting...