Astronomers Find First Intermediate Black Hole In The Milky Way
A supermassive black hole (not that old Muse song) is found in the center of almost every galaxy. They have the mass of million, possibly billions of Suns, believed to form through the merging of intermediate-mass black holes. However, these have never been detected in the Milky Way – until now.
A paper published in Nature recently announced that researchers from Harvard and the University of Queensland have discovered an intermediate-mass black hole in the Milky Way. It weighs 2,200 times the mass of the Sun and is about 13,000 light-years from Earth. Before this discovery, these black holes were merely assumed to exist. Black holes were previously thought to come in two varieties: small stellar-size ones (only between a few times the mass of the Sun to tens of times) and the aforementioned supermassive variant. In 2012, scientists thought they had found an intermediate-mass black hole in a galaxy 300 million light-years away, but more work is needed to confirm this.
Lead author of the studyBülent Kiziltan, from the Harvard-Smithsonian Center for Astrophysics (CfA), said in a statement: “We want to find intermediate-mass black holes because they are the missing link between stellar-mass and supermassive black holes,”
“They may be the primordial seeds that grew into the monsters we see in the centers of galaxies today.”
The thing about black holes is that they are really hard to detect. The nature of a black hole means that nothing can escape its pull – not even light. You can’t actually look directly at them. So, in the deep blackness of space, they are invisible. This made finding the monster lurking in the the stellar cluster 47 Tucanae extremely difficult. Usually, astronomers wait for one to inhale stars or gas to see the powerful light emitted. However, 47 Tucanae has no gas in it, so the team looked at how the stars and pulsars around it moved.
This is a very complex way to find black holes, but the data remains true. Trajectories and speeds of the bodies in 47 Tucanae show that a large black hole is there.
The method and discovery also show that there could be more of these intermediate light-eaters lurking about or galaxy. Don’t worry though, they’re far enough away not to cause any dramatic harm to us… for now.
If you fancy yourself Johnny Eagle-Eye, you can head over to the Auckland Stardome and have a look for yourself. They’re also doing a few Valentine’s Day deals, so its also a way to get into your favorite aspiring-astronomers good books.