A Rogue Planet With No Star Drifts Through the Galaxy in Total Darkness Forever

Imagine a planet the size of Jupiter, with no sun, drifting alone through the dark vastness between stars. There is no day, no warmth, no fixed direction. The only light comes from distant stars.

These are rogue planets, and astronomers now think they may be more common than stars. A 2021 study by researchers at NASA and the University of Bordeaux estimated there could be hundreds of billions of rogue planets in the Milky Way alone.

How They Form

Rogue planets are typically formed in two ways:

• Ejection: A young planetary system, full of gravitational chaos, can fling planets out into interstellar space
• Direct collapse: Some planet-sized objects form like miniature stars, from collapsing gas clouds, but never reach the mass needed for fusion

Could They Host Life?

Surprisingly, possibly yes. Some rogue planets retain enough internal heat — from gravitational compression and radioactive decay — to keep subsurface oceans liquid for billions of years. Without a sun, life on rogue planets would have to depend on geothermal energy, much like organisms around Earth's hydrothermal vents.

The Closest Known Rogue Planet

OTS 44, about 470 light-years away, is one of the smallest known rogue planets — only about 11 times the mass of Jupiter. It even has its own dust disk, suggesting it could form moons of its own.