Moon overview

Moons come in many shapes, sizes, and types. A few have atmospheres and even hidden oceans beneath their surfaces. Most planetary moons probably formed from the discs of gas and dust circulating around planets in the early solar system, though some are captured objects that formed elsewhere and fell into orbit around larger worlds.

Scientists are getting so good at spotting tiny moons orbiting distant, giant planets that the International Astronomical Union, which governs official names of planets and moons, will no longer name the smallest moons unless they’re of “significant” scientific interest. There are likely thousands more moons awaiting discovery in our solar system.