Black holes are one of the most extreme and mysterious things in the universe. They are both fascinating and scary. Many astronomers think that supermassive black holes are at the center of all large galaxies. These space-time singularities have pulls on them that are so strong that no light can escape.
Now, scientists from the National Optical-Infrared Astronomy Research Laboratory (NOIRLab) have found the closest black hole to Earth. According to a statement from the research team, it is close enough to be in our “cosmic backyard.”
The black hole, called Gaia BH1, is about 1,560 light-years from Earth. It is in the constellation Ophiuchus, which is about 1,500 light-years from Earth. Its mass is almost 10 times that of our sun.
Oddly, Gaia BH1 is also circled by a star that looks like the sun. This star is about the same distance from Gaia BH1 as the Earth is from the sun. Astronomers say that binary systems like this one are rare. In fact, this is the first one of its kind to be found in the Milky Way.
“While there have been many claimed detections of systems like this, almost all these discoveries have subsequently been refuted,” wrote Dr. Kareem El-Badry, who led the study. “This is the first unambiguous detection of a sunlike star in a wide orbit around a stellar-mass black hole in our galaxy.”
Astronomers think there may be as many as 100 million black holes in the Milky Way, but “they’re just isolated, so we can’t see them,” El-Badry said.
Most black holes start out as massive stars that are five to ten times the size of the sun. As they get close to the end of their lives, their cores start to fuse denser elements together to make iron, which takes more energy to make than it gives off.
Once this happens, the star can’t handle its own gravitational force and huge mass anymore, so it explodes in a supernova and then collapses in on itself, sucking in any nearby matter and creating a singularity. A singularity is an infinitely dense, dimensionless force of gravity that is so strong that no light can escape past a point called an event horizon.
There are a lot of ideas about what happens to matter when it falls into a black hole, from time distortion to traveling to other universes to “spaghettification,” a process in which the strong gravity of the black hole rearranges, compresses and expands the atoms of an object into an unrecognizable shape that looks like spaghetti noodles.
Scientists can often find black holes in the universe because these super-dense objects give off X-rays as they pull in more matter. Smithsonian Magazine says that people often say that these live black holes are “feeding.”
But Gaia BH1, named after the European Space Agency’s GAIA spacecraft that tracks the positions and movements of stars in the Milky Way, is not a feeding black hole. It is inactive and doesn’t give off X-rays. In fact, there are more dormant black holes, but they are harder to find.
Researchers first got a hint that Gaia BH1 existed not because they saw X-ray emissions but because they saw a nearby star in the Ophiuchus constellation move in a strange way.
BREAKING 🚨: Astronomers have found the closest known black hole to Earth, just 1,600 light-years away pic.twitter.com/MdWJvD5fKs
— Latest in space (@latestinspace) November 6, 2022
Using information from several other telescopes, they were then able to figure out that the strange movements of the star were caused by the gravitational pull of an unknown massive object, in this case a black hole.
Astronomers were even more confused about why Gaia BH1 hadn’t eaten that nearby star when it went supernova.
El-Badry said in a statement, “It poses many questions about how this binary system was formed, as well as how many of these dormant black holes there are out there.”
When the GAIA spacecraft sends out its next set of data in 2025, it may help answer some of these questions.