A billion light-years away from our Milky Way is a galaxy called PG1211+143. As in almost all galaxies, including ours, a black hole gravitates within it. Using the European Space Agency (ESA) X-ray observatory, British astronomers have been able to detect a novel phenomenon. They published their findings in the Monthly Notices of the Royal Astronomical Society journal.
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'During the span of a day, we managed to follow a mass the size of the Earth, while it was falling into a black hole,' says the lead author of the study, Dr. Ken Pounds from the University of Leicester. They noted that during its descent, the matter accelerated to reach a speed of 62,000 miles per second (mps), or 'a third of the velocity of light.'
A gas that forms rings before being absorbed
The speed is tremendous, which researchers have managed to determine by observing the spectrum of gas being swallowed by the black hole. During this event, the gas begins to orbit around the hole forming an accretion disk, that is to say a sequence of circular orbits whose diameter gradually decreases. The closer the spiraling gas is to the event horizon, the faster it spins.
Nevertheless, for the scientists part of the process remains unclear, especially when it comes to the alignment between the orbiting gas and that of the black hole. In PG1211+143, the team was able to observe that the gas was misaligned with respect to the rotation of the black hole due to an effect called Lense-Thirring or 'frame-dragging.' Thus subjected to extreme force, the disk decomposes into several rings that are interlocked.
Because of these collisions, the rotation of the rings was halted and the matter fell directly into the black hole instead of slowly rotating while descending. A series of unprecedented observations has seemed to confirm the theoretical work conducted by the astrophysicists.
A lead in the explanation of the supermassive black holes’ formation
'The galaxy we observed has a black hole 40 million times the mass of our sun. It is very bright, and very well fed,' says Dr. Pounds. 'Fifteen years ago, we noticed strong winds which suggested that perhaps it was being overfed, and we know now that these winds are present in many active galaxies. However, this is the first time we have detected matter falling directly into the black hole.'
This study opens a new door in the vast field of the study of black holes. Dr. Pounds suggests that this phenomenon of the 'chaotic accretion' of the misaligned disks is more common around supermassive black holes than we had previously believed. It could even be the norm rather than an exception and occur in the majority of black holes.
According to scientists, these black holes could rotate slower than expected and thus be able to ingest more gas from all directions and increase their mass even quicker. This could explain the supermassive black holes formed at the birth of our universe and how they rapidly acquired such large masses.
