The smaller and outermost of the planet Mars' two moons. Deimos was discovered by Asaph Hall on August 11, 1877. In Greek mythology, Deimos was the son of Ares (Mars) and Aphrodite (Venus) and was the personification of "Panic".
Deimos (meaning "terror") is the smaller of the two tiny moons of Mars. Deimos is only 7.8 miles (12.6 km) across and has a mass of 1.80x10 15. It orbits at a mean distance of 14,300 miles (23,000 km) from Mars. Deimos may be a captured asteroid. It was discovered by A. Hall in 1877.
Deimos (IPA or ; Greek Δείμος: "Dread"), is the smaller and outermost of Mars’ two moons (the other being Phobos). It is named after Deimos from Greek Mythology. Its systematic designation is Mars II.
In Greek mythology, Deimos ("dread") was the personification of dread. He was the son of Ares and Aphrodite. He, his brother Phobos, and the goddess Enyo accompanied Ares into battle, as well as his father's attendants, Trembling and Panic.