Astronomy

Black holes are regions of space where gravity is so strong that not even light can escape. How do they form, and what happens at the event horizon?

Stars are unimaginably far away. What methods do astronomers use to measure stellar distances, and how far is our closest stellar neighbour?

The universe began in an extremely hot, dense state about 13.8 billion years ago. What do physicists understand about what caused or preceded it?

Gravity pulls the Moon toward Earth, so why does it stay in orbit instead of crashing into us?