July 17, 2013
Supermassive Black Hole At Heart Of Milky Shreds Enormous Gas Cloud
[ Watch the Video: Simulation of Gas Cloud Being Ripped Apart By Black Hole ]
Lee Rannals for redOrbit.com - Your Universe Online
Astronomers writing in the Astrophysical Journal say the gas cloud being ripped apart by the Milky Way's supermassive black hole is now so stretched that its front portion has passed the closest point and is traveling away from the black hole at more than six million miles per hour.
Scientists first discovered a gas cloud several times the mass of the Earth accelerating towards the black hole in 2011. This cloud has been steadily moving toward the behemoth space object, and the new observations show it is finally being stretched by the black hole's intense gravitational field.
"The gas at the head of the cloud is now stretched over more than 160 billion kilometers around the closest point of the orbit to the black hole. And the closest approach is only a bit more than 25 billion kilometers from the black hole itself - barely escaping falling right in," explained Stefan Gillessen of Max Planck Institute for Extraterrestrial Physics in Garching, Germany who led the observation team.
"The cloud is so stretched that the close approach is not a single event but rather a process that extends over a period of at least one year."
The team was able to measure the velocities of different parts of the cloud as it streaks past the central black hole. They were able to do this by observing the region close to the black hole for more than 20 hours of total exposure time with the VLT's SINFONI instrument.
"The most exciting thing we now see in the new observations is the head of the cloud coming back towards us at more than 10 million km/h along the orbit - about 1 percent of the speed of light," added Reinhard Genzel, leader of the research group that has been studying this region for nearly twenty years. "This means that the front end of the cloud has already made its closest approach to the black hole."
Gillessen said the cloud is now being stretched out so much that it is starting to resemble spaghetti. "This means that it probably doesn't have a star in it. At the moment we think that the gas probably came from the stars we see orbiting the black hole."
Scientists from around the world with telescopes capable of observing this event will be able to provide plenty of new data, which will in turn shed more light on one of the universe's biggest mysteries.