'Doomed gas cloud rushing toward black hole'
Paris: Astronomers have spied a giant gas cloud with several times the mass of Earth accelerating towards the supermassive black hole at the centre of our own Milky Way galaxy.
The doomed cloud has a rendezvous with oblivion in mid-2013, when it will pass within 40 billion kilometres – a hair's breadth on astronomical scales -- of the voracious, matter-sucking void, according to a study to be published in Nature on January 5.
"It is not going to survive the experience," said Stefan Gillessen, a research at the Max-Planck Institute of Extraterrestrial Physics and lead author of the study.
With a mass four million times that of the Sun, the black hole's irresistible gravitational pull will rip the gas cloud into shreds over the next few years, he said.
This will be the first time ever that scientists will be able to observe in realtime the destruction of such a gas cloud by a supermassive black hole.
Over the last seven years, the speed of the cloud -- observed with the European Space Agency's Very Large Telescope in Chile -- has doubled to about eight million kilometres per hour.
Far cooler than the surrounding stars, it is composed mostly of hydrogen and helium, and has a mass roughly three times that of Earth.
The cloud glows under the strong ultraviolet radiation from the hot stars around it in the Milky Way's crowded centre.
As it approaches the black hole, the gas cloud will heat up and begin to emit X-rays.
"There is currently little material close to the black hole, so the newly-arrived meal will be the dominant fuel for it over the next few years," ESO said in a statement.
Scientists speculate that the cloud formed from the cast-off debris of nearby hot-burning young stars that rapidly lose mass due to strong stellar winds.
"The next two years will be very interesting and should provide us with extremely valuable information on the behaviour of matter around such remarkable massive objects," said Rienhard Genzel, also an astronomer at Max-Planck and head of the team that wrote the study.
The black hole at the centre of the Milky Way -- known as Sagittarius A star, or Sgr A* -- is by far the closest supermassive black hole known.
By definition, a black hole is a region in spacetime from which nothing, including light, can escape due to its gravitational force.