Artist's illustration of two stars orbiting a black hole. Photo: ESO/L. Calçada
A black hole found just 1,000 light-years from Earth is the closest yet found to our planet.
Why it matters: The relatively nearby black hole — which is orbited by two stars — presents scientists with the opportunity to learn more about these mysterious objects by studying one not too far from our own part of the galaxy.
"There must be hundreds of millions of black holes out there, but we know about only very few. Knowing what to look for should put us in a better position to find them," Thomas Rivinius, an author of the new study about the black hole in the journal Astronomy & Astrophysics, said in a statement.
Details: The black hole is about four times the mass of the Sun, and unlike many of the other black holes found in our galaxy, it isn't actively feeding off of its surroundings.
- Instead, the black hole is "truly black," according to the researchers who discovered it, and isn't gobbling up surrounding matter, which would cause it to glow in X-ray light.
- The two stars circling the black hole effectively appear to be orbiting a black point in space, which can only be a black hole.
- Keen observers in the Southern Hemisphere may even be able to see the stars that circle the black hole with the naked eye from dark areas.
Context: Scientists think that the type of black hole found in the HR 6819 system form during the deaths of massive stars, but other, larger black holes like the one in the center of the Milky Way form through different, still unknown means.
What's next: The scientists behind the new study think that there is already another good candidate system that looks similar to HR 6819.
- "LB-1 is a bit further away from Earth but still pretty close in astronomical terms, so that means that probably many more of these systems exist," Marianne Heida said in the statement.
- Astronomers also think they can study these systems to learn more about how gravitational waves — which are caused by the mergers of two massive objects that literally ripple the fabric of space and time — occur in a system with three large objects.
Go deeper: The hunt for a new kind of black hole