Moons of Mars Moons of Mars The two moons of Mars are Phobos and Deimos. Both were discovered by Asaph Hall in August 1877 and are named after the Greek mythological twin characters Phobos (panic/fear) and Deimos (terror/dread) who accompanied their father Ares, god of war, into battle. Ares was known as Mars to the Romans. Phobos orbits closer to Mars, with a semi-major axis of to Deimos' . The existence of the moons of Mars had been speculated about since the moons of Jupiter were discovered. It is known that when Galileo, as a hidden report about him having observed two bumps
Moons of Uranus these five, Titania, is 1,578 km in diameter and the eighth-largest moon in the Solar System, and about one-twentieth the mass the Earth's Moon. The orbits of the regular moons are nearly coplanar with Uranus's equator, which is tilted 97.77° to its orbit. Uranus's irregular moons have elliptical and strongly inclined (mostly retrograde) orbits at large distances from the planet. William Herschel discovered the first two moons, Titania and Oberon, in 1787, and the other three ellipsoidal moons were discovered in 1851 by William Lassell (Ariel and Umbriel) and in 1948 by Gerard Kuiper (Miranda). These five have planetary mass,