Black Hole Mercilessly Rips Apart Gas Cloud with the Mass of Several Earths

Black holes are destructive, ripping apart material with the immense force of their gravity. Once inside, nothing can escape a black hole's relentless pull--not even light. Now, scientists have discovered a gas cloud with several times the mass of Earth accelerating toward a black hole at the center of the Milky Way. Researchers are now getting a closer look at how material interacts with black holes.

Using the ESO's Very Large Telescope, scientists first discovered the gas cloud in 2011. At the time, this object was much cooler than the surrounding stars (only about 280 degrees Celsius), and was composed mostly of hydrogen and helium. It is a dusty, ionized gas cloud, and glows under the strong ultraviolet radiation from the hot stars around it in the crowded heart of the Milky Way. Now, this cloud of material is making its closest approach, becoming grossly stretched by the black hole's extreme 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," said Stefan Gillessen, who led the observing team, in a news release. "And the closest approach is only a bit more than 25 billion kilometers from the black hole itself--barely escaping falling right in. 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."

As the gas cloud stretches, its light becomes harder to see. Yet scientists stared at the region close to the black hole for more than 20 hours of exposure time in order to get around that issue. Using the SINFONI instrument on the VLT, they were able to measure the velocities of different parts of the cloud as it streaked past the central black hole.

"The most exciting thing we now see in the new observations is the head of the cloud coming back toward us at more than 10 million km/h along the orbit--about one percent of the speed of light," said Reihard Genzel, one of the researchers, in a news release. "This means that the front end of the cloud has already made its closest approach to the black hole."

The origin of this cloud of gas is unknown, but scientists are continuing to watch its path toward the black hole. The climax of this unique event is currently unfolding, which means that researchers are eagerly expecting to gather a wealth of new data. The new findings could reveal more about the gas cloud and could probe regions close to the black hole that have not been previously studied.

The findings are published online here.