Astronomers find closest black hole to Earth
Astronomers have found the closest black hole to Earth. But don’t worry, our planet is not about to get sucked in, as it's 1,600 light years away.
Astronomers using the Gemini North telescope on Hawaii – one of the twin telescopes of the International Gemini Observatory – spotted the black hole which the researchers have dubbed Gaia BH1.
This dormant black hole is about 10 times bigger than the sun and is located in in the constellation Ophiuchus.
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It is three times closer to Earth than the previous record holder, an X-ray binary in the constellation of Monoceros.
The new discovery was made possible by making exquisite observations of the motion of the black hole's companion, a sun-like star that orbits the black hole at about the same distance as the Earth orbits the sun.
"Take the solar system, put a black hole where the sun is, and the sun where the Earth is, and you get this system," explained Kareem El-Badry, an astrophysicist at the Center for Astrophysics, Harvard & Smithsonian and the Max Planck Institute for Astronomy, and the lead author of the paper describing the discovery.
"While there have been many claimed detections of systems like this, almost all these discoveries have subsequently been refuted.
“This is the first unambiguous detection of a sun-like star in a wide orbit around a stellar-mass black hole in our galaxy."
Black holes are the most extreme objects in the universe. Supermassive versions of these unimaginably dense objects likely reside at the centres of all large galaxies.
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Stellar-mass black holes – which weigh approximately five to 100 times the mass of the sun – are much more common, with an estimated 100 million in the Milky Way alone.
Though there are likely millions of stellar-mass black holes roaming the Milky Way galaxy, those few that have been detected were uncovered by their energetic interactions with a companion star.
"I've been searching for dormant black holes for the last four years using a wide range of datasets and methods," said El-Badry.
"My previous attempts – as well as those of others – turned up a menagerie of binary systems that masquerade as black holes, but this is the first time the search has borne fruit."
The team originally identified the system as potentially hosting a black hole by analysing data from the European Space Agency's Gaia spacecraft.
"Our Gemini follow-up observations confirmed beyond reasonable doubt that the binary contains a normal star and at least one dormant black hole," explained El-Badry.
"We could find no plausible astrophysical scenario that can explain the observed orbit of the system that doesn't involve at least one black hole."
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