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Mars is very cold, very dusty, and has a thin atmosphere that is saturated with carbon dioxide gas. Sometimes it gets so cold that the carbon dioxide condenses onto the martian surface. So why do we want to go there? Because Mars wasn't always this way. Thirty years of research in the form of spacecraft flybys, orbiters, and landers has revealed that Mars was once Earthlike. The fingerprint of a water planet lies in its landforms. Large channels and small gullies attest to a history of flowing water. There is the possibility that life may have existed there and might even exist there today.

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  More About Mars
  • Fourth planet from the Sun, the next beyond Earth
  • Revolves around the Sun once every 687 Earth days
  • Length of a martian day: 24 hours, 39 min., 35 sec.
  • Atmosphere is mostly carbon dioxide (95.3 percent), nitrogen (2.7 percent), and argon (1.6 percent)
  • Surface winds up to 40 meters per second (80 miles per hour)
  • Surface temperature averages -53C (-64 F);
  • Surface temperature varies from -128C (-199 F) during polar night to 27 C (80 F) at equator during midday
  • Gravity only 38 percent as strong as Earth's
  • Two irregular moons, each only a few kilometers wide: Phobos (larger moon) and Deimos (smaller)
  • Average diameter 6,780 kilometers (4,212 miles); about half the size of Earth, but twice the size of Earth's Moon
  • Average distance from the Sun 227.7 million kilometers (141.5 million miles)
  • Distance from Earth varies from 54,500,000 kilometers (33,900,000 miles) to 401,300,000 kilometers (249,000,000 miles)
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