Mars is a cold desert world. It is half the diameter of Earth
and has the same amount of dry land. Like Earth, Mars has
seasons, polar ice caps, volcanoes, canyons and weather, but its
atmosphere is too thin for liquid water to exist for long on the
surface. There are signs of ancient floods on Mars, but evidence
for water now exists mainly in icy soil and thin clouds.
Featured Mission: Mars Science Laboratory/Curiosity Curiosity, a
robotic rover about the size of a small SUV, is designed to find
whether the Red Planet ever was -- or is still today -- an
environment suitable for life. The rover landed on Mars in
August 2012. Read More About Mars