Black Holes: Where Reality Beats Fiction

We know that at the heart of pretty much every galaxy, there is a giant black hole. There is a lot that we know about black holes — and a lot that we don't know, says astrophysicist Marcelo Gleiser.

Why Riding An Elevator Is Like Changing Gravity

If you time it just right, tossing a ball in the air as an elevator starts to move, the ball seems to hang in the air for a moment, like gravity had been canceled, says astrophysicist Adam Frank.