To make a black hole, do we have to squeeze mass all the way to its limit, or do we just have to get close enough?
It turns out that black holes might have hair after all.
What if black holes don’t exist, but similar objects do? How would we tell the difference?
There’s news of a mysterious alignment of black holes. While that makes for good headlines, the actual scientific findings aren’t so mysterious.
Inside the galaxy known as NGC 1600 there is a black hole 17 billion times more massive than our Sun.
If you were to spin a ball, for example, the texture of the ball’s surface would make it easy to see the ball is rotating. But what if the ball were perfectly smooth?
To help distinguish a real signal from the noise you need to know what a real signal might look like. That means you need to use general relativity to create models of things such as binary black holes.
While there is lots of evidence showing black holes exist, we’d really like to observe them more directly.
What would happen if two black holes merged near our solar system? While the real answer is complex, we can do a back of the envelope calculation.