Massive gas cloud falling into Milky Way’s black hole to meet its end

A gas cloud that is destined to be ripped, shredded and largely eaten in just a few years is invading the normally quiet neighbourhood around the massive black hole at the centre of our Milky Way Galaxy, according to scientists.

Many, if not all, galaxies have massive black holes at their centres. But this super-massive black hole is the only one close enough for astronomers to study in detail, so the violent encounter is a unique chance to observe what until now has only been theorized: how a black hole gulps gas, dust and stars as it grows ever bigger.

“When we look at the black holes in the centres of other galaxies, we see them get bright and then fade, but we never know what is actually happening,” said Eliot Quataert, a theoretical astrophysicist and University of California, Berkeley professor of astronomy.

“This is an unprecedented opportunity to obtain unique observations and insight into the processes that go on as gas falls into a black hole, heats up and emits light. It’s a neat window onto a black hole that's actually capturing gas as it spirals in,” Quataert noted.

Reinhard Genzel, professor of physics at both UC Berkeley and the Max Planck Institute for Extraterrestrial Physics (MPE) in Garching, German, noted, “The next two years will be very interesting and should provide us with extremely valuable information on the behaviour of matter around such massive objects, and its ultimate fate.”

Since 2008 Genzel, Stefan Gillessen of the MPE, Quataert and their team have seen the gas cloud about three times the mass of Earth speeding up as it has fallen deeper into the gravitational whirlpool of the black hole. Its edges are already beginning to fray.

“It is not going to survive the experience,” said Gillessen.

By 2013, scientists should see outbursts of X-rays and radio waves as the cloud" composed mostly hydrogen and helium gas gets hotter and is torn asunder. The light emitted around the black hole could increase by a hundredfold to a thousandfold, Quataert calculated.

The discovery has been recently reported in the British journal Nature.