I see, hear, and read about black holes and their consumption power often. They grow as they consume. Eventually, as they keep growing and consuming, wouldn’t they combine and continue the process until they become so large as to devour everything in existence?
In: Physics
Weirdly enough, collapsing into black holes actually has the exact opposite effect.
Earth spins around its own centre once every 24 hours (give or take). As a result, anything that’s orbiting Earth far enough away to take more than 24 hours to go all the way around – such as the Moon for example – is actually getting very slowly *pushed away* (or pulled away rather) by the Earth’s gravity.
Very, *very*, slowly. The Moon was probably twice as close a few billion years ago. With a B.
This pulling-away gravity effect is known as a tidal force, named after the tides we see on Earth when the oceans pull-push the Moon (and to a lesser extent, the Sun).
If Earth suddenly collapsed into a black hole, its mass wouldn’t change. Its angular momentum would be the same. But its radius would be much smaller, so it’d spin much faster, so instead of sucking in and eating the Moon, Earth would actually push/pull it away *faster*.
We think. We’re pretty sure that’s how black holes work, but for obvious reasons we’ve never observed it directly. We do know it’s how they work when two black holes orbit each other.
Latest Answers