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
Transit of Phobos from Mars 57.75 seconds to get a time of 20:49:02.4 UTC for the center of the shadow. Putting in the longitude/latitude/altitude coordinate values -124,14,0 into JPL Horizons gives an expected time of 20:49 for the transit, which is in good agreement once again. On 1 September 1999 the distance between the Earth and Mars was 9.9 light-minutes. Transit of Phobos from Mars A transit of Phobos across the Sun as seen from Mars takes place when Phobos passes directly between the Sun and a point on the surface of Mars, obscuring a large part of the Sun's disc for an observer on