Astronomers have measured a Saturn-mass object apparently drifting through the Milky Way without a star—and microlensing surveys suggest that unseen free-floating worlds may outnumber the galaxy’s stars, perhaps by as much as 20 to one.

Astronomers have measured a Saturn-mass object apparently drifting through the Milky Way without a star—and microlensing surveys suggest that unseen free-floating worlds may outnumber the galaxy’s stars, perhaps by as much as 20 to one.

A short gravitational microlensing event observed from Earth and the Gaia spacecraft has given astronomers a direct mass estimate for an object with no detected host star. The lens, designated KMT-2024-BLG-0792/OGLE-2024-BLG-0516, has a mass of about 0.22 Jupiter masses, or roughly 70 Earth masses. That makes it slightly less massive than Saturn. Subo Dong and 41 colleagues reported the measurement in a January 2026 paper in Science. Their analy…