The two moons of Mars hold several distinctions in the solar
system. Phobos, the innermost moon of Mars, is the closest
moon to any planet in the solar system. Phobos is less than
3700 miles (6000 km) from the surface of Mars. In contrast, the
Earth's moon is 240,000 miles (384,400 km) from the Earth. Deimos,
the outermost and smaller moon of Mars, is one of the smallest known
moons in the solar system. Both of moon's names are derived from
the Greek language. Phobos is Greek for fear and Deimos is Greek
for panic
Many scientists believe that Phobos and Deimos are captured
asteroids from the outer solar system, but there are other
scientists who counter this idea. Both moons have a low density,
which means that they cannot be made of pure rock, but rather a
mixture of rock and ice. Another similarity between the two moons
is that they are both heavily cratered. Deimos does have a slightly
smoother appearance, due to the filling of some of its craters. One
of the main features on Phobos is a large impact crater. The impact
was so severe that scientists think the impact probably came close
to shattering the moon. Striated patterns from the impact can be
traced over a large portion of the landscape of Phobos.
Science On a Sphere
