NASA Satellite May Have Found The Smallest Known Black Hole

In what is turning out to be one of the best months ever for black-hole fanbois, a team of Dutch, Italian, and US space boffins has detected the "heartbeat" of what appears to be teensiest, weensiest black hole ever discovered.


"Just as the heart rate of a mouse is faster than an elephant's, the heartbeat signals from these black holes scale according to their masses," said University of Amsterdam's Diego Altamirano, referring to the newly discovered IGR J17091-3624 and a similar object, GRS 1915+105.


While GRS 1915+105 is a black-hole pipsqueak with a mass only 14 times that of our sun, IGR J17091-3624 is tinier still, estimated to be a mere three times as massive as Ol' Sol, a size that is close to the theoretical "mass boundary" at which the formation of a black hole becomes possible.


Compare those anorexic celestial bodies to the supermassive black hole discovered early this month, which is 10 billion times as massive as our li'l sun. Or, for that matter, to the two other black holes that turned up this month, one busily slurping a gas cloud and another being born.


An international team of astronomers utilizing NASA’s Rossi X-Ray Timing Explorer (RXTE), believe that they’ve identified a candidate for the smallest known black hole. Using the RXTE, which detects X-rays coming from cosmic sources, the astronomers were able to identify a specific X-ray pattern – nicknamed a “heartbeat” – that indicates that a black hole is present in a binary system with the ordinary star. The “heartbeat” pattern is caused by the regular cycles of matter accumulated into the black hole from its neighboring star.


As the stellar matter (mostly gas) circles the event horizon of the black hole, its heated up to temperatures of millions of degrees, a process which causes X-rays to be emitted. The explusion of X-rays then temporarily pushes the gas away from the black hole, which is what causes the cyclical heartbeat-type pattern.


If the astronomers’ calculations are correct, this black hole is located about 16,000 to 56,000 light years away from Earth (a more precise distance hasn’t yet been determined). The black hole itself is only about three times the mass of the Sun, which means that the original star was just barely big enough to form a black hole. Our Sun, by contrast, lacks sufficient mass to form a black hole at the end of its life-cycle.


The astronomers plan to use this new data in conjunction with a similar X-ray pattern from another small black hole. As they continue to use that data and new data from the RXTE, they hope to learn more about smaller black holes and confirm that this X-ray heartbeat is really the sign of one.