Space questions, answered
What is a black hole?
A black hole is a region of space where gravity is so strong that nothing — not even light — can escape once it falls in. Most form when a massive star collapses at the end of its life.
The boundary of no return is called the event horizon; cross it and you can't get back out. Black holes aren't cosmic vacuum cleaners — from a safe distance their gravity behaves like any other mass of the same size — but up close, they warp space and time to extremes.
They range from a few times the Sun's mass up to the supermassive black holes at the centres of galaxies, millions or billions of times heavier. The first direct image of one, in galaxy M87, was captured in 2019.
People also ask
Is there a black hole in the Milky Way?
Yes — a supermassive one called Sagittarius A*, about four million times the Sun's mass, at the galaxy's centre. It was imaged in 2022.
Sources: NASA — black holes