Scans of empty space show black holes near Earth.

• Gaia BH3, the third black hole discovered by the European Space Agency’s Gaia telescope, is located close to the Earth.

• Black holes are observable due to their unique effects on their surroundings, causing matter to compress, heat up, and emit X-rays.

• The Gaia spacecraft has been observing quiet black holes not associated with X-ray emissions.

• The star’s orbit in space is projected by Gaia, and ground-based telescopes track how light from the star is shifted by the Doppler effect.

• The star’s mass is estimated based on the orientation of the star’s orbit in space and the mass inside the ‘blank’ space.

• The first black hole discovered by Gaia was Gaia BH1, located about 1,560 light years away and the closest black hole to the Earth yet.

• Gaia BH2 was discovered by a team of scientists headed by Kareem El-Badry from the California Institute of Technology.

• Gaia BH3 is the first black hole astronomers have found in the Milky Way galaxy’s outer reaches and the largest known stellar-mass black hole in the galaxy.

• The discovery was made in July 2023, after astrophysicist Pasquale Panuzzo discovered the largest stellar-mass black hole to date.

• Gaia BH3 is located about 2,000 light years away in the constellation Aquila and appears to be a passive black hole, indicating it lacks a significant supply of matter in its neighborhood and does not have associated X-ray emissions.

• The discovery is a rare occurrence in astronomical research, with further data from ground-based telescopes confirming its mass.