Rogue Planets

space · planets · astronomy · lonely worlds

Planets without homes. Rogue planets are massive objects similar in size to Earth or Jupiter, but they drift through space completely alone. Unlike Earth, which orbits the Sun, these planets have no star pulling them along, so they wander endlessly through the darkness.

Hard to spot. Scientists have discovered about 70 rogue planets so far, but there could be trillions more hiding in space. They're incredibly difficult to find because they don't glow like stars do and don't reflect light from a nearby sun.

Cold and dark. Without a star to warm them, rogue planets are frozen and pitch black. Some scientists think they might still have heat left over from when they formed, which could keep them warmer than you'd expect deep underground.

Kicked out or created. Some rogue planets were probably ejected from their star systems after collisions with other planets long ago. Others may have formed in the empty space between stars, never having a home solar system to begin with.

Mysteries in the cosmos. Finding rogue planets helps scientists understand how planets form and why some stick with stars while others go free. They might even be the most common type of planet in the universe.