Mars Facts

Everything you need to know about the Red Planet — in bite-sized form.

All Atmosphere Geology History-formation Moons Orbit-distance Temperature Water-ice
moons

Mars Has Two Tiny Moons

Phobos and Deimos are Mars's two small, irregularly shaped moons, likely captured asteroids. Phobos orbits so close to Mars that it completes an orbit in just 7 hours 39 minutes — faster than Mars rotates — and will eventually crash into the planet in roughly 50 million years.