AstroLab
The two moons of Mars
Phobos races; Deimos takes its time.
Watch Phobos complete an orbit in 7 h 39 min, while Deimos takes about 30 h 18 min. Time advances by ten minutes per second.
Why explore it?
Phobos orbits faster than Mars rotates. Their distances from the center are 9,378 and 23,459 km, compared with about 384,400 km for Earth’s Moon. The view uses a shared scale compression for all moons. The periods are real; orbital phases in this circular model are illustrative.