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AriG
30th September 2012, 13:26
Not a very clearly written article. Nonetheless, just wanted to pass this along.http://www.forbes.com/sites/alexknapp/2012/09/29/astronomers-measure-the-radius-of-a-black-hole/

Paul
1st October 2012, 03:42
Not a very clearly written article. Nonetheless, just wanted to pass this along.http://www.forbes.com/sites/alexknapp/2012/09/29/astronomers-measure-the-radius-of-a-black-hole/
From the article:



With the Event Horizon Telescope, astronomers can. The accretion disks innermost orbit is about 70 billion miles roughly 5 times the size our entire solar system. After careful calculation and observation, they determined that the accretion disk is about 5.5 times the size of the black hole itself, giving them an estimate of the radius.
That's a bit vague in my book, because it is not well defined how large the solar system is. The planet Uranus orbits about 2.8 billion miles from the sun. The above statement that the accretion disks are 70 billion miles out, and that that is 5.5 times the size of the black hole, imply that the black hole is estimated to be 12.7 billion miles in radius, which would be 12.7/2.8 == 4.5 times further out than the orbit of Uranus.