Scientists have discovered new evidence that there is a huge black hole at the center of our galaxy, by watching as material approaches the event horizon.
In a paper published in Astronomy and Astrophysics, an international team used an instrument on the European Southern Observatory’s (ESO) Very Large Telescope in Chile to study the suspected supermassive black hole, called Sagittarius A*.
That instrument is called GRAVITY, which combines the light from the four VLT telescopes to create a virtual “super-telescope” that’s 130 meters (430 feet) in diameter.
Using GRAVITY, the team were able to observe flares of infrared radiation coming from Sagittarius A*. It’s thought these flares come from clumps of hot gas that’s orbiting near the event horizon, the point at which the gravity is so intense that nothing, not even light, can escape the black hole’s pull.
This material is thought to be moving at tremendous speeds, about a third the speed of light. The closest it can get to the black hole without crossing the event horizon is known as the innermost stable orbit, where the flares came from.
"It’s mind-boggling to actually witness material orbiting a massive black hole at 30% of the speed of light," said Oliver Pfuhl, a scientist at the Max Planck Institute for Extraterrestrial Physics (MPE) and a co-author on the study, in a statement. "GRAVITY’s tremendous sensitivity has allowed us to observe the accretion processes in real time in unprecedented detail."
These findings are said to be proof that this supermassive black hole really exists. The gas is believed to be linked to a star called S2, which under Einstein’s theory of general relativity would cause the bright flares when it swings near the black hole every 16 years, noted Astronomy Online.
And this is also the first time we’ve seen material so close to the black hole. It gives us an interesting look at “the funhouse-mirrored space-time that surrounds a black hole,” noted Quanta Magazine, which is a rather lovely way to describe this region.
Now astronomers hope to use findings like this to study black holes in more detail, including how they can fire out violent jets of energy from galaxies. “It’s a bit like knowing that the sun is a hot, gaseous sphere and trying to understand how the nuclear reactions work,” Roger Blandford, a professor of astrophysics at Stanford University, told the New York Times.
There’s also a project taking place right to try and image Sagittarius A* directly, called the Event Horizon Telescope (EHT), which would be our first ever image of a black hole. So it’s pretty good news that we can now conclusively confirm the black hole is there.