It's Official: Black Holes Have Lots Of Mass

KewlPC writes "Spaceflight Now reports in this article that some scientists have been able to measure the "weight" (yeah, yeah, it's actually mass, not weight) of a black hole that is (or was, 13 billion years ago) eating up the most distant known quasar, some 13 billion light years away."

Comments

Duh.

[Ayanami Rei]

Even I knew that. I mean, stuff keeps falling in them. You know that last significant figure to which they measured the weight? About 10^-8 percent of that are my keys, for sure.

Neat

[Anonymous Coward]

This is neat, I'd never heard of this before:

The extreme brightness of this quasar also shows that the black hole in its core is swallowing matter at the maximum rate possible. This maximum rate is called the "Eddington Limit". If the black hole were accreting matter any faster, it would shine even brighter, and the intense luminosity would actually exert enough pressure to stop any more material falling in.

So there's a limit / "max throughput" to how much matter a black hole can suck in? Very interesting.

Re:Neat

[ndevice]

this is how normal stars work too. The radiation pressure generated by the core keeps the core from collapsing into itself. - well not quite the same, but same idea.

But I haven't heard of the eddington limit before either. Neat.

Re:Does this say anything about its size?

[ndevice]

You might be confusing neutron stars (pulars sometimes) with these quasars.

Neutron stars are prevented from collapsing into black holes because of nuclear repulsion / neutron degeneracy (instead of electron repulsion). In fact, there's so much pressure that the electrons get squeezed into the protons of the atoms - hence neutron stars.

Black holes have enough gravity to overcome nuclear repulsion and collapse further than neutron stars. I think there's a couple theories about just what happens inside the black hole, but the commonality is that particles don't mean much whether or not you're talking about a singularity, or the non-singularity quantum foam theories.

interstellar dust reddens

[barakn]

Atoms produce very specific patterns of absorption or emission in the light spectrum depending on species. A familiar example, is the solar spectrum, which is created by absorption of narrow bands in the spectrum by a large number of different elements in different states of ionization. Redshift causes the entire set of these lines to be moved towards the red end of the spectrum. They retain the spacing between themselves, so they can still be recognized in their new positions, and their new positions tell us how fast the object that created them is moving. Reddening caused by dust doesn't move these absorption lines. Instead it scatters light preferentially at the blue end of the spectrum, causing the entire end of that spectrum to dim, rather than creating narrow bands in it or moving narrow bands around. These two different processes are usually distinguishable.

Re:Does this say anything about its size?

[taliver]

Actually, a quick googling found this:

r0=2GM/c^2 (Eqn 10.1.5)

So it is directly proportional. However, I didn't look closely at the units that they are using here, but thta shouldn't matter to the solution at hand.