Researchers have discovered the very first rogue black hole, and it’s less than 5,000 light-years away. The astronomers detected and measured the mass of an isolated stellar-mass black hole over the course of several years. They’ve now published their results in a new study.
Astronomers have detected a rogue black hole
Previously, all the stellar-mass black holes that we’ve detected were in binary systems. However, the discovery of a rogue black hole could open new mysteries around these space-bound entities. Scientists discovered the black hole around 5,000 light-years away from Earth. It’s located towards the bulge in the center of our galaxy, the Milky Way.
Astronomers first noted the existence of the rogue black hole in 2011. At the time, the researchers noted a possible microlensing event. Essentially, a microlensing event is when the gravitational force of an object causes the light of a star to bend. This is something often seen around black holes, as they pull the light of nearby stars towards them. It’s also seen around stars or white dwarfs.
Following the initial discovery, astronomers began observing the microlensing event, looking for new clues to the cause. For six years, the researchers watched as the light changed, hoping to catch a glimpse of the black hole they suspected was there. However, they also noticed that the position of the star appeared to change, too.
This led the team to believe an object passing by was the cause of the changes. They continued to watch and observe the changes and eventually were able to rule out the microlensing being the cause of the light changes.
Instead, everything they found led them to believe that a rogue black hole could be the culprit.
What’s the big deal anyway?
The reason that a rogue black hole has garnered so much interest is because of the implications it brings to what we know about black holes currently. As noted above, previous discoveries have shown that black holes usually are only found in binary systems.
As such, seeing a black hole on its own, without a star, is a big deal. It could mean that there are other black holes out there, that we just aren’t able to see yet.
Knowing that rogue black holes exist is only part of the equation, though. We’ll still need to find them, which could be extremely difficult as black holes are often dark. The main reason that researchers were even able to discover this one was due to changes in the light from stars beyond it.
