A Stray Black Hole Is Hiding Somewhere In The Milky Way

Astronomers have recently discovered a rogue black hole within the Milky Way galaxy.

Business Insider reported that a rogue black hole was discovered hiding within a high-speed cosmic cloud at the corner of the Milky Way galaxy. While scientists have only found 60 black holes out of hundreds of millions of them (with the closest one located 3,000 lightyears away from Earth), the discovery has given them clues on where some of the black holes must be located.

"We found a new way of discovering stray black holes," Professor Tomoharu Oka, an astrophysics professor at Keio University and author of the study, said in a statement.

For the study, the team used the ASTE Telescope in Chile and the 45-meter Radi Telescope at Nobeyama Radio Observatory. While they were observing several molecular clouds near the scraps from a supernova explosion named SNR W44, they found a stray black hole located 10,000 lightyears away.

With a speed of 100 km per second, the team named the cloud "the Bullet." It is about 300 times the speed of sound in space and is behaving in an unusual way.

"Most of the Bullet has an expanding motion with a speed of 50 km/s, but the tip of the Bullet has a speed of 120 km/s," study's lead author Masaya Yamada, a graduate student at Keio University in Japan, said, according to Phys.org. "Its kinetic energy is a few tens of times larger than that injected by the W44 supernova. It seems impossible to generate such an energetic cloud under ordinary environments."

The team came up with two conclusions explaining the Bullet's strange behavior. First is the "explosion model," where the gas shell of the supernova remnant may have passed by a black hole and created an explosion. The activity must have accelerated the gas towards the Earth after it whipped past the black hole.

Another equally potential explanation is the "shooting model," where high-speed black hole must have stormed through the gas. The black hole's strong gravity must have dragged the gas along, which eventually formed a gas stream.

The study is published in The Astrophysical Journal Letters.