The Closest Black Hole to Earth Is Gaia BH1 at Only 1,600 Light-Years Away

Key Takeaways on the Closest Black Hole to Earth

• The closest black hole is Gaia BH1, and it’s about 1,600 light-years away from our planet, Earth.
• Though Gaia BH1 is the closest black hole to Earth, the black hole is dormant.
• Gaia BH1 is a stellar black hole, and while it’s large, it’s nothing compared to the size of supermassive black hole TON 618, which has an equal mass to 60 billion suns.

Black holes are incredibly powerful astral forces, sucking in and absorbing anything that comes within light-years. They can absorb planets, stars, and even each other, uniting to form even larger black holes. Supermassive black holes usually sit at the center of all large galaxies, including our Milky Way.

But does this mean we have anything to fear? What is the closest black hole to Earth? And does the supermassive black hole at the center of the Milky Way pose any danger to us?

The short answer is no: the closest black hole to us, Gaia BH1, is hundreds of light-years away and it’s dormant. And TON 618, the largest black hole yet discovered, is an order of magnitude farther away from Earth.

“We should be super happy that we discovered them and we can consider them as a friend,” says Sara Rastello, an astrophysicist at the University of Barcelona who has studied Gaia BH1.

Read More: Two Black Hole Mergers Emitted Gravitational Waves, Upholding Einstein's Theory of Relativity

The Closest Black Hole: Gaia BH1

Astronomers published their discovery of Gaia BH1 in 2023, after discovering it with the European Space Agency’s Gaia satellite, which operated from 2014 to 2025. The satellite measured how stars, mostly in our galaxy, moved.

Among the many discoveries was a black hole that sat relatively close to our galaxy, only about 480 parsecs from Earth. A parsec is a unit that represents the average distance between the sun and Earth. This means that Gaia BH1 is about 1,560 light-years away.

While this makes Gaia BH1 the closest black hole yet discovered, it’s really no cause for concern for a number of reasons. For one, even the fastest spacecraft we currently have would take about 40 billion years to arrive there, Rastello says — “much longer than the age of the universe.”

What Is A Dormant Black Hole?

All black holes are difficult to observe because they don’t emit light. Astronomers often observe black holes based on the glow of material that surrounds them, called an accretion disc. This disc is basically the material being pulled towards the black hole, but hasn’t yet passed the event horizon — basically the point of no return.

The trouble is, Gaia BH1 has no accretion disc — it’s not actively pulling in material. As such, Gaia BH1 is referred to as a dormant black hole. The only reason scientists discovered its presence was due to the orbit of a star about the size of our own sun that was bound to it.

This star had a warbling orbit, leading scientists to believe it was moving around something, but that something was dark. Since nothing was visible, they identified the force as a black hole.

“It’s like we spot the invisible,” Rastello says.

The companion star is still pretty far from the black hole — it orbits around the black hole every 185 days at about 1.3 times the average distance between the Earth and sun.

“At the moment, the system is completely stable,” Rastello says. “The sun-like star and the black hole are far enough apart that no mass transfer occurs.”

This binary is relatively isolated in the disc of the Milky Way, so it’s unlikely something else will interfere with this system. But in a few billion years, the star may expand into a red giant, at which point it may start losing material to Gaia BH1, which would then become active.

Dormant black holes are a relatively new discovery, Rastello says. But now that astronomers know how to look, “we expect to find a lot of them.”

Using the Gaia satellite, they’ve already found two more — Gaia BH2 and Gaia BH3 — at distances of 3,800 and 1,900 light-years away from Earth, respectively. Gaia BH2 has a similar mass to Gaia BH1 and is orbiting a red giant rather than a star in its main sequence. But Gaia BH3 is massive — about 33 times the mass of our sun — the biggest stellar black hole yet discovered in the Milky Way, Rastello says.

Why Is TON 618 So Scary?

Despite the dormant classification, you still wouldn’t want to fly a spaceship anywhere near Gaia BH1. Astronomers estimate Gaia BH1 is about nine times the mass of our sun.

But true giants like the supermassive black hole TON 618 are in an entirely different class to Gaia BH1 or even Gaia BH3, both stellar black holes. Sitting at the center of a galaxy more than 10 billion light-years away from us, TON 618 was first discovered by the Tonantzintla Observatory in Mexico in the mid-20th century. TON 618 is a supermassive black hole with an estimated mass of about 60 billion suns.

Supermassive black holes often sit at the center of galaxies — the one at the center of our Milky Way is called Sagittarius A*, and it’s only about 26,000 light-years away. Sagittarius A* is about 4.3 million solar masses — massive, but a fraction of the size of TON 618.

To compare just how big TON 618 is in relation to our sun, our entire solar system, and even other black holes, NASA created an animation several years ago. Rastello says that supermassive black holes like TON 618 are usually the opposite of dormant, actively eating all the material that surrounds them. This is why scientists can observe them — their accretion discs are massive.

While perhaps scary for some, Rastello sees black holes far differently.

“They are actually fascinating objects,” she says. “By studying them, we learn a tremendous amount about how stars, galaxies, and even the universe evolve.”

Read More: A Binary Star Neighbors Our Galaxy's Supermassive Black Hole

Article Sources

Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:

• This article references information from the recent study published in Monthly Notices of the Royal Astronomical Society. Dynamical formation of Gaia BH1 in a young star cluster
• This article references information from the recent study published in Monthly Notices of the Royal Astronomical Society. A Sun-like star orbiting a black hole
• This article references information from NASA: NASA Animation Sizes Up the Universe’s Biggest Black Holes