About the image. Drawn with a glowing disk to make it visible. The real Gaia BH1 is dormant: it is not feeding, gives off almost no light, and was found only through its companion's motion.
Most black holes we know of announce themselves: they pull gas off a companion star, and the gas heats up and blazes in X-rays. Gaia BH1 does nothing of the kind. It sits quietly in the constellation Ophiuchus, about 1 560 light-years away, and is the nearest system astronomers are reasonably confident contains a black hole.
Found by a wobble
The European Space Agency’s Gaia spacecraft measures the positions of more than a billion stars with exquisite precision. In its data, a team led by Kareem El-Badry noticed a Sun-like star tracing out a loop every 185 days around something it could not see. Follow-up measurements of the star’s speed confirmed the orbit. Whatever it is circling weighs about nine and a half Suns and is completely dark. No star that heavy could hide like that. The team found no explanation other than a black hole. A second, independent team detected it too.
Small and heavy
For its mass, Gaia BH1’s event horizon is tiny: a radius of only about 27 kilometres.
Its discovery suggests that the Milky Way contains many more silent black holes than we have found, each one invisible unless something happens to be orbiting it.
How long to get there?
Gaia BH1 is about 1 560 light-years away.
Light299 792 km/s1 560 years
Breakthrough Starshotplanned light sail, 20% of light speed7 800 years
Parker Solar Probefastest spacecraft so far, 192 km/s2.4 million years
Voyager 1leaving the Solar System, 17 km/s27.5 million years
At Voyager 1's speed the trip would take about 343 879 human lifetimes of 80 years. Bars are on a logarithmic scale. Speeds: NASA, Breakthrough Initiatives.
Gallery
Artist's impressions rendered from the same model as the view at the top of this page.
Timeline
2022Announced from Gaia data and follow-up measurements.
2024Black hole mass refined to about 9.3 Suns.
Questions people ask
What is the closest black hole to Earth?
Gaia BH1, about 1 560 light-years away, is the nearest system astronomers are reasonably confident contains a black hole.
How was Gaia BH1 found?
Gaia saw a Sun-like star moving in a loop around something invisible. Follow-up measurements showed the unseen companion weighs about nine and a half Suns.
Is Gaia BH1 dangerous?
No. It is far away and dormant, not feeding on gas.