Black hole

A black hole is a region of space where the pull of gravity is so strong that nothing, not even light, can escape from it.

Formation

Black holes usually form when a massive star collapses at the end of its life. Supermassive black holes, millions of times the mass of the Sun, sit at the centres of most galaxies.

Event horizon

The boundary around a black hole is called the event horizon; once matter crosses it, it cannot return. In 2019 astronomers captured the first image of a black hole's surroundings.

Frequently asked questions

What is a black hole?

A region of space with gravity so strong that not even light escapes.

How do black holes form?

Usually from the collapse of a massive star.