The Surface

Mars Facts

  • Surface Gravity = 3.72 m/s2 or 0.38 of Earth's gravity
  • Surface Temperature = -220 to 70 degrees Fahrenheit (average = -81) or -140 to 20 degrees Celsius (average = -63)

    • The surface of Mars can be divided into three major regions:
    • Southern Highlands
    • Northern Plains
      • plains
      • crustal upwarps - Elysium, Tharsis regions
    • Polar Regions
    The Southern Highlands is an extensive region. It has high terrain that is heavily cratered like the moon. The Southern Highlands are thought to be an ancient region, because of the heavy density of craters -- most cratering in the solar system happened in a period long ago.


    Photo courtesy NASA/JPL/Malin Space Science Systems
    Mars Global Surveyor view of Galle crater
    in the Southern Highlands

    The Northern Plains are low-lying regions, much like the maria, or seas, on the moon. The plains show lava flows with small cinder cones -- evidence of volcanoes -- as well as dunes, wind streaks, and major channels and basins similar to dry "river valleys." There is a distinct change in elevation, of several kilometers, between the Southern Highlands and the Northern Plains.

    In the Northern Plains, there are two continent-sized, high regions called crustal upwarps. These upwarps are areas where the molten rock from the interior mantle has pushed or bulged the planet's thin crust up, forming a high plateau. These regions are capped with shield volcanoes, where molten rock from the magma broke through the crust. The smaller region, called Elysium, is in the eastern hemisphere. The largest one is called the Tharsis region and is located in the western hemisphere.


    Photo courtesy NASA/JPL/Malin Space Science Systems
    Mars Global Surveyor view of the Tharsis region showing the volcanoes (covered by blue-white clouds) and the Valles Marineris canyon (lower right)

    The highest mountain in the solar system is located in the Tharsis Region. This mountain is a shield volcano called Olympus Mons (Mt. Olympus from Greek mythology). Olympus Mons rises 16 miles (25 km) above the surrounding plains and it is 370 miles (600 km) wide at its base. In contrast, the largest volcano on Earth is Mauna Loa in Hawaii, which rises 6 miles (10 km) above the ocean floor and is 140 miles (225 km) wide at its base.


    Photo courtesy NASA/NSSDC
    Color mosaic of Olympus Mons from Viking 1 orbiter


    Photo courtesy NASA/MOLA Science Team
    Topographic view of Olympus Mons

    At the edge of the Tharsis Region is a large system of canyons called Valles Marineris. Valles Marineris is 2,400 miles (4,000 km) long, which is greater than the distance from New York to Los Angeles. The canyons are 420 miles(700 km) wide and 20,000 feet (4.2 miles or 7 km) deep. As you can see, Valles Marineris is much larger than the Grand Canyon. Unlike the Grand Canyon which was formed by water erosion from the Colorado River, Valles Marineris was created by cracking of the crust when the Tharsis bulge formed.


    Photo courtesy NASA/JPL/USGS
    Central region of Valles Marineris
    as seen from Mars Global Surveyor

    The Polar Regions can be seen from the Earth. The polar ice caps are made mostly of frozen carbon dioxide (dry ice) with some water ice. The size of the polar ice caps varies with the season. In the summer, the carbon dioxide from the northern ice cap sublimes, revealing a sheet of water ice below. It is not known whether the southern ice cap has a similar sheet of water ice beneath it. Surrounding the polar ice caps are vast regions of dunes.


    Photo courtesy NASA/NSSDC
    Viking 2 orbiter color mosaic of the south pole of Mars


    Photo courtesy NASA/MOLA Science Team
    Topographic view of Mars north pole