August 17, 2023
On this date in 1877, American astronomer Asaph Hall discovered one of the two moons of Mars, which he named Phobos. In mythology, Phobos is one of the sons of Ares, the Greek counterpart to the Roman god of war, Mars. Only five days prior, on August 12, 1877, Hall had discovered the Martian moon Deimos, also named for a son of Ares. Phobos and Deimos remain the only two Martian moons discovered.
Mars’ moons Phobos (left) and Deimos (right). The names mean “fear” and “panic” respectively. Image credit: NASA