Scientists Discover Closest Known Black Hole to Earth
Black holes are incredibly massive and numerous — scientists believe there may be as many as 100 million in our galaxy alone — but they’re surprisingly hard to spot. Scientists from the Harvard & Smithsonian Center for Astrophysics believe they’ve just identified a dormant black hole just 1,600 light-years away in the constellation Ophiuchus, taking the crown as the closest one currently known. This unusual solar system could also point to problems with our understanding of binary stars.
Many of the black holes we hear about are actively devouring stars and other objects. The spiral of superheated material in the accretion disk of these black holes makes them bright in X-rays, aiding in detection. However, scientists suspect there are many more that aren’t easy to see. This newly discovered black hole, dubbed Gaia BH1, is the first confirmed dormant black hole in a binary system, something astronomers have long hunted.
The first sign of something unusual in this binary system came from the European Space Agency’s Gaia spacecraft, which has been working to produce the most detailed 3D map of star locations and motion in the Milky Way. Gaia identified a sun-like star that appeared to wobble as it orbited an unseen partner. This is similar to how astronomers use radial velocity measurements to spot some exoplanets. Upon further investigation with the Magellan Baade telescope in Chile and Gemini North Telescope in Hawaii, the team confirmed the star is orbiting a stellar-mass black hole. This discovery has been published in the Monthly Notices of the Royal Astronomical Society.
Analysis shows the invisible monster is about 10 times the mass of our sun. Its companion appears to be in a stable orbit far enough away that it does not lose mass to the black hole. “Take [our] Solar System, put a black hole where the Sun is, and the Sun where the Earth is, and you get this system,” says lead author Kareem El-Badry.
The previous record-holder for the closest black hole was about 3,000 light years distant. That object was an active X-ray source in the constellation of Monoceros, making it easier to spot. Gaia BH1 will be easier to study at just 1,600 light-years away, and it’s going to get a lot of attention. In addition to confirming the Center for Astrophysics’ findings, astronomers will have to puzzle over how BH1 and its companion ended up where they are.
According to the team, the progenitor star that formed Gaia BH1 would have been at least 20 times the mass of the sun. Therefore, it would have survived only a few million years before burning out. Assuming it formed at the same time as its companion, BH1’s supergiant phase would have engulfed the sun-like star. All the theoretical models that predict a surviving companion star result in a tighter orbit than seen here. On the other hand, El-Badry says there is no plausible model in which the unseen companion is anything other than a black hole. Quite a cosmic mystery.
Continue reading
AMD Discloses a Spectre-Like Vulnerability in Zen 3 CPUs
AMD has disclosed a potential security vulnerability on its Zen 3 CPUs with similarities to the Spectre attack from several years ago, but the company believes the risk is minimal.
NASA’s Juno Spacecraft Snaps First Close-Ups of Ganymede in 20 years
NASA set Juno on course for a flyby of Ganymede on June 7th, marking the first time a spacecraft has made a close approach to the celestial body in more than 20 years.
New ‘Dragon Man’ Skull Could Represent Humanity’s Closest Ancestor
A new fossil discovery may have found a close ancestor of ours — or a link in the Denisovan family tree.
Starlink Is Already Getting Close to Wired Broadband Speeds
According to the latest data from Ookla Speedtest, Starlink has seen substantial speed improvements that put it close to wired broadband. It's even managed this while increasing subscriber counts by more than 25 percent.