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.
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