But recently astronomers have used data collected by the European Space Agency’s Gaia spacecraft to detect three previously unknown black holes and, it turns out, are the closest known to Earth.

Since it launched in December 2013, Gaia charted the cosmos from a vantage point about a million miles (1.6 million kilometers) from Earth, at a spot called Lagrange point 2 (L2), where the ...

Gaia has been peering into the universe from a stable orbit 1.5 million kilometers (930,000 miles) from Earth called the second Lagrange point. But the neighborhood has been getting more crowded ...

Europe's space agency, ESA, has retired the Gaia satellite after more than nine years of service. Launched in 2013, Gaia created the most detailed 3D ...