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#### More about Mars Hubble's sharpest view of Mars, taken March 10, 1997 Credits: Science@NASA Fourth planet from the Sun, the next after 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 moons, each only a few kilometres wide: Phobos (larger moon) and Deimos (smaller) Average diameter 6,780 kilometres (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 kilometres (141.5 million miles) Distance from earth varies from 54,500,000 kilometres (33,900,000 miles) to 401,300,000 kilometres (249,000,000 miles) Source: Cornell University Check that you understand what these words mean in this document To revolve: to move round a central point. Martian: the adjective deriving from the word Mars. Surface wind: a w ind close to the surface. For further information visit: NASA Mars Atlas