Cosmic cuisine: Giant gas blob on menu for Milky Way's black hole
Scientists who spotted a giant gas blob orbiting the black hole at the center of the Milky Way say they'll get a first-ever close-up view of matter falling into a supermassive black hole.
For the first time, astronomers are poised to get a close look at a supermassive black hole making a meal of in-falling gas.Skip to next paragraph
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The black hole in question lurks in the center of the Milky Way. A vast blob of gas is orbiting the black hole, known astronomically as Sagittarius A*. And it appears to be a swan-song orbit.
At its closest approach in 2013, the gradually stretching blob will have been shredded into fragments by the black hole's gravity. The fragments are expected to swing to within 1.5 light-days of the black hole's event horizon – the point of no return for in-falling matter.
That's about 260 times the distance between Earth and the sun. The team discovering the blob calculates that some of the gas fragments will be flung into new orbits around Sagittarius A*. But the team says some of that gas may be drawn in ever-tightening circles around the black hole until it crosses the event horizon and vanishes in a burst of radiation.
IN PICTURES: The Milky Way
"What a unique opportunity!" says an enthused Stefan Gillessen, an astrophysicist at the Max Planck Institute for Astrophysics in Garching, Germany. Dr. Gillessen led the team reporting the results in Thursday's issue of the journal Nature.
Researchers observing other galaxies millions of light-years away claim to have seen stars being disrupted by black holes, Gillessen writes in an email exchange. But the level of detail in the data hasn't been high enough to be thoroughly convincing.
"Here, we can predict that an accretion event will happen, [and] at a very close distance of 25,000 light years," he says. "The mass being fed towards the black hole is small, but we can watch it in exquisite detail."
In some ways this sounds a bit like hungry waifs staring through a restaurant window as a diner is about to take in a fork tipped with filet mignon.
But Gillessen and others say the observations will help draw a more complete picture of how black holes operate.
Such an event would help show how galactic black holes gain mass over time. And the fragments' interactions with gas already in the region could serve as a probe of environmental conditions in the black hole's immediate backyard.
Black holes are cosmic objects with so much mass squeezed into such a small volume that the strength of their gravity prevents even light, traveling at 186,000 miles a second, from escaping.
Stars far more massive than the sun typically end their lives as so-called stellar-mass black holes. These tend have the mass of about 10 suns with an event horizon only about 18 miles across.
But black holes also come supersized – behemoths stuffed with the mass of millions or billions of suns and whose event horizons can reach out to several times the distance between the sun and Pluto. These supermassive black holes are said to reside at the center of nearly all galaxies and play important roles in their evolution.