Watery Mars

An image compiled from observations by the orbiting Mars Odyssey spacecraft shows an abundance of water on Mars. The image, which is centered on the north pole, is color coded by the amount of water ice mixed with other materials. Water makes up more than half of the material at and around the polar ice cap (blue and purple), while it accounts for less than 20 percent of the total at lower latitudes (red). Over the last 15 years, a series of Mars-exploring orbiters, rovers, and landers has found large amounts of water in the polar ice caps and mixed with the dirt, and evidence of possible large deposits below the surface. [NASA/JPL/Univ. Arizona]