Last Reviewed:August 30, 2022 by Gabrielle Marks
Does Mars Have Moons? Mars has two small, misshapen moons that orbit the planet – Deimos and Phobos. They are among the smallest in the solar system. American astronomer Asaph Hall discovered the moons in 1877. Hall named them after the sons of the Greek god of war, Ares, who is the Greek counterpart to the Roman god Mars.
Phobos – Mars Larger Moon
Image Credit: NASA
Phobos, whose name means fear or panic, is the larger of Mars’s two moons, averaging 69.7 km in equatorial circumference. To get a sense of how small that is, compare it to the equatorial circumference of the Earth’s moon, which is 10,917. Km. Orbiting at the height of only 6,000 km above the Martian surface, Phobos is the lowest orbiting moon currently known, making a complete orbit of the planet 3 times per day.
Mars Won’t Always Have Two Moons
Due to Phobos’ unusually low orbit, Mars’ gravitational tidal forces are dragging it closer to Mars at a rate of six feet every hundred years. NASA speculates that in 50 million years or so, these gravitational tidal forces will cause the moon to collide with Mars shattering it into oblivion. The debris caused by the collision may form a decaying ring around Mars.
Deimos – Mars Smaller Moon
Image Credit: NASA
Deimos, whose name means flight or “to flee,” is the smaller of Mars’ diminutive moons, with an average equatorial circumference of only 38 km across. However, unlike his brother Phobos, Deimos has a much higher orbit at just over 20,000 km above the planet’s surface and requires about 30 hrs to orbit the planet.
