When Black Holes Collide

EricTheGreen writes "CNN.com reports on a pair of black holes in a mating dance that can only end badly for both of them. Fortunately they've still got several million years for the emotional rush to wear off and realize what a terrible mistake they're both making..."

Sooner than you think

[Skevin]

> Fortunately they've still got several million years

Umm, how many light years away is this? Sure, it might take million years for the *light* from the spectacle of them merging to reach us, but if they're millions of light years away (center of the galaxy?), they may have already merged.

I've always speculated as whether gravity travels like light. Would "gravity waves" from the merge be felt here on earth the instant it happened, or would it take the same amount of time as light/electromagnetic radiation to reach us?

something I always wondered

[Fëanáro]

Something I always wondered:
When two black holes are close together, then something that has exactly the same distance to each of them should not fall into either one.

What happens when they are so close that their event horizons overlap?

Shouldn't there always be some flat zone between them that is not part of either event horizon?

So how can they merge?

Re:Oh boy

[chrismcdirty]

I propose we call them star holes, since they're in space and they suck up stars, among other things.

Re:Sooner than you think

[ComaVN]

Even if (just a hypothesis) gravity waves reaches here at the instant it happened, it means that it is not detectable, since if we can detect it, it means information travelled at more than the speed of light.

Alternatively, it could mean that no information can travel at more than the speed of light, except in the form of gravity waves.

I mean, shouldn't "No Information can travel at the speed more than that of light" really be "There's no known mechanism by which information can travel at a speed more than that of light"?