Largest Black Hole Measured 170
porkpickle tips us to a BBC article on the quasar OJ287, a binary object containing largest black hole yet discovered, weighing in at 18 billion times the mass of Sol. Researchers were able to estimate its mass due to the presence of a smaller black hole in orbit around it. When the smaller companion's orbit intersects OJ287's accretion disk, once every 12 years, it triggers a burst of radiation that was detected by the Spitzer Space Telescope. More detail and a diagram are available on the Turku University site.
eh? I don't get it? (Score:4, Interesting)
I mean, if they used the word "massive" I'd get it. But large?
Question about gravity (Score:5, Interesting)
Re:orbiting blackholes? (Score:3, Interesting)
Re:Question about gravity (Score:3, Interesting)
(In fact if the singularity somehow disappeared magically the outside world wouldn't detect it since the signal of black hole disappearing wouldn't escape from the gravitational well.)
Re:orbiting blackholes? (Score:3, Interesting)
Re:Question about gravity (Score:3, Interesting)
Hence, gravity is not affected by gravity.
In gauge theory, a non-Abelian gauge group will in general lead to a nonlinear Yang-Mills theory with self-interacting fields, in contrast to the linear Abelian theory of electrodynamics.
Because gluons, the mediator of the strong nuclear force, themselves carry strong ("color") charge, it's possible for them to bind to each other. (See glueballs [wikipedia.org] in quantum chromodynamics.)
Similarly, gravity gravitates: gravitons interact with each other, because they have energy and anything with energy gravitates. This idea holds even in classical general relativity: gravitational fields themselves gravitate. Analogously to QCD glueballs, general relativity can have gravitational geons [wikipedia.org], which are regions of gravitational field which hold themselves together under their own gravity. (You might think that a vacuum black hole has that property too, but I'm talking about purely non-singular field configurations.)
Re:That's incredible! (Score:2, Interesting)
Re:Now I don't get it! (Score:3, Interesting)