How do black holes grow so large?

New Euclid study shows galaxy collisions feed the giants

- Chris Lintott

The question of how black holes grow should be an easy one to answer: they absorb material from their surroundings. But despite their fearsome reputation, supermassive black holes don't rampage through their host galaxies; instead, they can be found sitting quietly in the middle. And while it's true that material that comes too close to them will inevitably fall in, most of the stuff in a galaxy is far enough away to be safe. As long as we don't get too near, we have nothing to fear from the black hole at the centre of the Milky Way.