Rogue Planet Discovered: Saturn-Sized World Drifts Alone in Milky Way

• Scientists discovered a Saturn-sized 'rogue planet' (free-floating planet) that does not orbit any star, drifting alone 10,000 light-years away towards the Milky Way's center.
• Discovered via gravitational microlensing, where the planet's gravity bent a distant star's light, observed by KMTNet, OGLE, and ESA's Gaia Space Telescope.
• Its mass is 22% of Jupiter's, making it similar to Saturn; this is the first precise measurement of a rogue planet's mass and distance.
• The discovery fills the 'Einstein Desert' gap for mid-range mass rogue planets and suggests such ejected planets could be more numerous than stars.
• Published in Science journal on January 1, 2026, by international scientists including Subo Dong and Andrzej Udalski.

Why It Matters: First precisely measured Saturn-sized rogue planet found, suggesting abundant starless worlds.