The black hole is seven solar masses in size and is moving at 45 kilometers per hour.
A possible gravitational microlensing event in the cosmos witnessed in 2011 was due to a black hole floating through interstellar space, the first of its kind ever observed.
“We report the first unambiguous detection and mass measurement of an isolated stellar-mass black hole ,” says an international team of astronomers led by Kailash C. Sahu of the Space Telescope Science Institute on the arXiv preprint server .
hard to see
Scientists have assumed for some time that there are plenty of black holes roaming interstellar space, but until now they haven’t found any. This is due to the very nature of a black hole : they are difficult to detect against the black background of space.
Still, the evidence for its existence was strong. Previous research has shown that black holes often form when stars reach the end of their lives and their cores collapse, usually producing a supernova. And because so many such supernovae have been observed, it seemed clear that many black holes must have been created as a result .
But finding them has meant looking for lensing effects, when starlight is bent by the black hole ‘s pull . Given the great distances, lensing is slight, making it almost impossible to detect even with the best modern telescopes.
In 2011 when two project teams looking for such lenses saw a star that seemed to shine for no apparent reason. Intrigued, the researchers began to analyze data from the Hubble Space Telescope. For six years, they watched the light change, hoping that the change was due to the enlargement of a black hole . Then they found something else: the star’s position seemed to change.
The researchers suggest that the change could only be due to an unseen moving object exerting a force that tugged on light as it passed by: an interstellar black hole . The researchers continued to study the star and its light, eventually ruling out the possibility that the light came from lensing and also confirming that the magnification was long-lived, both of which are prerequisites for confirming the existence of a black hole , reports Phys. .org.
Taken together, the evidence is strong enough to confirm the sighting of a free-floating black hole . The researchers were even able to measure its size, at seven solar masses. They also found that it travels at approximately 45 km/h. (EuropePress)