One summer night in 1877, American astronomer Asaph Hall was looking through his telescope in Washington, D.C. Mars was at its closest point to Earth in its orbit, and Hall had one question on his mind: Does the Red Planet have a moon?
After multiple nights of searching in heavy fog, Hall spotted not just one but two moons, which he named Phobos and Deimos, the "terror" and "panic" twins in Greek mythology whose parents were Ares and Aphrodite (Mars and Venus in Roman mythology). These moons, however, look very different from our own — and scientists still have a lot of questions about their origins.
