Two supermassive black holes discovered in close orbit, possible merger

Miscellaneous Topics
#1

Ars Technica has an article about two supermassive black holes discovered in a close orbit:

Seven percent of light speed is already incredibly fast, and these are massive bodies, of billions of sun masses. I really wonder what will happen once their event horizons will begin to overlap.

And, unfortunatley beyond or reach of inspectation, will there be two singularities inside the merged even horizon, or two? Will the event horizon have the shape of a sphere, or will it wobble for a while?

Damnit, I want to watch and learn what happens there. Poor galaxy though, I assume the process will yield enough energy to disrupt the galaxy. Or maybe not?

What do you think about this?

#2

Interesting article, thanks for posting!
Unfortunately we will not see the result:

[quote]The two supermassive black holes of PG 1302-102 will not remain in their absurdly fast orbit forever. Rather, they’re expected to spiral into one another and merge in about a million years.
[/quote]
I don’t really understand how the event horizon of a black hole can stop light and matter escaping yet the force of gravity still escapes and interacts with everything else like normal.

#3

1 millions light years closer and we could see it right now! I want a warp drive!

Gravity is such a strange thing - it is usually seen as a force, but it also bends the time-space-continuum, an effect that the other forces don’t exhibit.

The bent is the reason why light and matter can’t escape, they run straight (from their point of view) but the space is bent by the gravity so that they actually run in circles (seen from outside the bent region).

The bent time-space near the black hole also affects the surroundings, it doesn’t stop at the event horizon. I guess that’s why we see the effect of gravity, but not light nor matter emitting from the black hole.

While the latter isn’t entirely true. If Hawking is right, quantum effects allow matter to tunnel the even horizon in some cases, so that black holes emit matter, but at a very low rate.

#4

It helps to picture a bowling ball placed on an elastic tarp. The bowling ball bends the tarp down, creating a slope.

If you were to pick up a little wind-up toy that moves at a given speed, and placed it on the slope, trying to climb out of it, as you placed it closer and closer to the bowling ball, there’d be a point where the toy wouldn’t be able to climb out.

Now, imagine taking a red marker and drawing a circle on the tarp around the bowling ball at the precise distance where the wind-up toy can no longer climb out.

The bowling ball is any object with mass.
The tarp is space (in 2d).
The tarp sloping towards the ball is gravity (the gravity well).
The wind-up toy is a photon moving at light speed.
And the red line you drew, that’s what we call the event horizon.

Event horizons are not an actual thing, they’re just an arbitrary name we’ve given to the point were light can no longer escape, because, since lightspeed is the fastest speed possible, if light can’t escape, nothing else can.

As for why light cannot escape but gravity can, the example illustrates that gravity is not like magnetism, a force transmitted by a particle moving at lightspeed, but rather, it is the shape of the universe at that given point.

The tricky part of this example, is trying to imagine the whole thing happening in three dimensions rather than the tarp’s two.

Hope that helped.