Astronomers Planning To Image Milky Way's Central Black Hole 68
99luftballon writes "Astronomers are planning the Event Horizon Telescope project in Arizona on Wednesday — and say in three or four years they should be able to image the ring of matter around the supermassive black hole at the center of the Milky Way. The black hole is 26,000 light years away, but should be large enough to check if Einstein got his equations right."
They won't see anything (Score:2, Informative)
It's black. Duh.
Accretion disk, not event horizon (Score:5, Informative)
They're not imaging the event horizon, they're trying to image the accretion disk around the central black hole, and hoping they can see the event horizon's "shadow" against it. I doubt that we're going to be directly imaging the event horizon for the central black hole anytime soon.
The Milky Way's central black hole is 4.l million solar masses. The Schwartzchild radius of a static black hole of that mass is roughly 12.3 million km, or 17.7 x the radius of our sun. That's roughly 1/3 the size of Mercury's orbit. You could put it in the center of our solar system, and not devour a single planet (though they would start orbiting a *lot* faster).
Hold out your fist at arm's length. If you put the Milky Way's central black hole where our sun was, it would be roughly that big.
Now, imagine trying to see something that size, which is perfectly dark, from 27,000 light years away and you'll understand how difficult it would be to directly image it.
Re:Accretion disk, not event horizon (Score:4, Informative)
I doubt that we're going to be directly imaging the event horizon for the central black hole anytime soon. [...] Now, imagine trying to see something that size, which is perfectly dark, from 27,000 light years away and you'll understand how difficult it would be to directly image it.
Direct imaging of its event horizon is exactly what they're planning to do: http://arxiv.org/abs/0906.3899 [arxiv.org]
Re:What If... (Score:3, Informative)
Its actually a massive rotating bar:
http://www.dailygalaxy.com/my_weblog/2011/12/the-center-of-the-milky-way-is-a-massive-rotating-bar-of-stars.html [dailygalaxy.com]