Category: the Universe is safe for now

No, Black Holes Will Never Consume The Universe

“Yes, there will be a very, very small number of stars, planets, asteroids and more that do get consumed by black holes, but it will be less than 0.1% of all the matter presently in the Universe. Even dark matter will remain in the outskirts of galaxies, unable to be eaten by black holes.

You might think that after googols and googols of years, anything still present in a galaxy will eventually be consumed, but don’t forget about Hawking radiation: eventually, all the Universe’s black holes will decay, too. Before any substantial fraction of the remaining galactic matter — normal or dark — can be devoured, every black hole in the Universe will have completely decayed away. If something dear to you does fall into a black hole, don’t despair. Try waiting instead. If you’re clever enough, you’ll not only get its energy back again someday, but most likely its information, too.”

About a month ago, I gave a talk in Hungary at their big international event: Brain Bar, where I spoke about the biggest myths about black holes. One of them is the idea that eventually, if you wait around for long enough, black holes will consume the entire Universe. It makes sense to think that this could happen, since gravity is real, there are close to a billion black holes in our galaxy, objects do randomly collide with one another, and gravitational radiation cause all bound masses to eventually inspiral into one another. But, as it turns out, something else happens first.

The overwhelming majority of matter will never find its way into a black hole, and black holes won’t consume the Universe. Here’s what happens instead.