planet-formation

Rogue planets, also called free-floating planets, are planetary-mass objects that orbit no star. Some were ejected from planetary systems and some may have collapsed from gas clouds on their own. Microlensing surveys suggest they are common, and a thick hydrogen atmosphere could in theory keep a few of them warm enough for liquid water.

Every planet in our solar system grew from a thin disk of gas and dust that surrounded the young Sun 4.6 billion years ago. Modern telescopes now image these disks around other stars in stunning detail, revealing a process far more violent, chaotic, and fast than scientists once imagined.