For a long time, scientists have suspected that the center of our galaxy is home to a supermassive black hole. Such objects exist at the heart of most major galaxies in the universe — and astronomers started to speculate that the Milky Way might be counted among them after a bright radio source was detected at the galaxy’s center in 1974.
Since the signal was traced back to a small region located inside a larger radio-emitting structure called Sagittarius A, the radio source was given the name Sagittarius A* (pronounced “Sagittarius A-star”) and has since been surmised as a supermassive black hole, notes Discover Magazine.
After four decades of gathering evidence to support the claim, astronomers have made an incredible breakthrough which confirms that there’s a supermassive black hole hiding at the heart of the Milky Way, the European Southern Observatory (ESO) announced earlier today.
Using ESO’s Very Large Telescope (VLT) in the Atacama Desert of Chile, a team of European scientists have picked up three bright flares of infrared radiation that originate from the cloud of material — also known as an accretion disk — surrounding Sagittarius A*.
The emissions come from highly charged material orbiting very near the purported black hole’s event horizon — the point of no return from where anything that ventures too close is immediately sucked in by the object’s tremendous gravitational force.
The discovery was made possible by the VLT’s GRAVITY instrument, which peered into the heart of the Milky Way and unveiled the edge of Sagittarius A*. These observations confirmed that the object is indeed a supermassive black hole.
In addition, the GRAVITY investigation revealed that this monster black hole boasts a mass 4 million times larger than that of the sun — as determined by examining the motion of the most central stars, called S-stars, over a period of more than 16 years.
As the Inquisitr previously reported, the ESO has been studying the central region of our galaxy for more than two decades and has recently measured the orbit of an S-star dubbed S2 as it performed a very close flyby of Sagittarius A*.
Oliver Pfuhl, a scientist at the Max Planck Institute for Extraterrestrial Physics (MPE) in Germany and one of the researchers who made the discovery, described the revelation of the black hole’s edge as “mind-boggling.”
“We were closely monitoring S2, and of course we always keep an eye on Sagittarius A*. During our observations, we were lucky enough to notice three bright flares from around the black hole — it was a lucky coincidence!”
The flares were spotted by GRAVITY on a circular orbit just outside the object’s event horizon and signaled the presence of three “clumps of gas swirling around at about 30 percent of the speed of light.” This is the first time that astronomers have managed to observe material circling this close to a black hole’s event horizon, notes the observatory.
“ESO’s exquisitely sensitive GRAVITY instrument has added further evidence to the long-standing assumption that a supermassive black hole lurks in the center of the Milky Way,” officials from the observatory said in a statement.
These spectacular findings — which represent “the most detailed observations yet of material orbiting this close to a black hole,” according to the ESO — are detailed in a study published in the journal Astronomy & Astrophysics.
“This always was one of our dream projects but we did not dare to hope that it would become possible so soon,” said study lead author Reinhard Genzel, also from the MPE.