Mars' Second Moon
Size and Appearance
Phobos is not a sphere but looks like a deformed shape like a potato. Phobos is 17 miles across at its widest. They are believed to be asteroids that were captured by the gravity of Mars. It is the largest of the two moons that orbit Mars. At the time it was barely visible until 1969 when they sent a spacecraft and took pictures of the moon. There is a big crater 5 miles wide on the surface of Phobos named Stickney after the finders wife. If that crater were any bigger if could've blown Phobos to pieces.
It takes 7.7 hours to rotate around Mars. It can rotate twice around Mars before Mars can rotate itself. Phobos is slowly moving closer to Mars and in about 50 million years it will either crash into Mars or break apart by its gravity and form a ring around Mars.
Phobos was found by Asaph Hall in 1877. Phobos is named after " Phobos, The Greek God of Fear,"