Matter plunges into black hole at a THIRD THE SPEED OF LIGHT
Gas fell directly into the singularity rather than circling it more slowly
A black hole has been caught feasting at a colossal rate, with gas falling into it at around 33 per cent the speed of light. A new study observed gas around the supermassive black hole at the centre of PG1211+143, a galaxy about a billion lightyears away in the direction of Coma Berenices.
The supermassive black hole is, like many others of its kind, surrounded by a disc of gas. As gas is drawn by gravity towards the black hole, friction causes the disc to heat up and glow, creating an extremely bright region known as an active galactic nucleus.
University of Leicester professor of astronomy Ken Pounds, who led the team that made the discovery, said, “The galaxy we were observing with XMM-Newton [the X-ray space telescope] has a 40 million solar mass black hole, which is very bright and evidently well fed. Indeed some 15 years ago we detected a powerful wind indicating the hole was being over-fed.”
Usually the rotation of the disc causes gas to spiral into the black hole, slowing its acceleration. However, the light from PG1211+143 is extremely redshifted suggesting that it’s travelling at enormous speeds.
“We were able to follow an Earth-sized clump of matter for about a day as it was pulled towards the black hole, accelerating to a third of the velocity of light before… plunging directly into the hole itself,” says Pounds.
The gas had almost no rotation around the black hole, allowing it to approach extremely close to its event horizon and reach speeds of around 100,000 km/s; the speed of light is approximately 300,000 km/s.
It’s thought this strange behaviour is caused by a misalignment between the black hole’s rotation and the plane of its disc. It’s commonly assumed these two line up, but there is no reason to believe that this is always the case.
Pounds’ observations back up recent theoretical work which suggests that misaligned accretion discs create rings of gas that can collide with each other. When they do, clumps of gas are torn off and swallowed directly by the black hole.