What Happened to the Atmosphere on Mars?
Scientists think early Mars used to be rich with water and had a thick atmosphere of carbon dioxide. Today, Mars is cold and dry, lacking that thick atmosphere it once had. What happened? NASA scientists theorize that the atmospheric molecules might have gotten stripped off the planet and knocked into space through a process called “sputtering.” In “sputtering,” some of Red Planet’s ions rise to the top of the atmosphere and hit atmospheric molecules, lodging some into space.
Mars may be more susceptible to sputtering because the planet lacks an intrinsic magnetic field and ions can more easily swept away by the Sun’s large magnetic field. The Sun’s magnetic field is carried through the solar system by a stream of charged particles emitted from the Sun’s upper atmosphere called the solar wind. When the solar wind passes through Mars, the ions in Mars’ atmosphere can interact with the solar wind’s charged particles, rise to the top of the atmosphere, and crash into other molecules. (The solar wind can also interfere with the Earth’s magnetic field and cause power outages on Earth.) Several billion years of atmospheric molecules getting knocked, or sputtered, into space could explain the significant atmospheric change on Mars- especially since the solar wind is thought to be very strong at the beginning of our solar system history.
Animation of solar winds stripping off Martian atmosphere
Next Monday, NASA will test this theory by launching the first spacecraft to study the upper Martian atmosphere Mars Atmosphere and Volatile Evolution, or MAVEN, mission is a year long mission that will provide data on the current rate of gasses escaping to space and will gather enough information about relevant processes to allow extrapolation to the early days on Mars. Scientists can use this data to observe how the red planet’s climate has been affected through time by the atmospheric loss of gasses. The mission will also give clues on the conditions for a planet to be habitable and not habitable, perhaps allowing scientists to use their findings to assess if sustainable life on other planets is possible.
MAVEN launches on Monday, November 18, 2013 between 1:28pm to 3:28pm EST from Cape Canaveral Air Force Station’s Space Launch Complex 41 in Florida. The spacecraft will launch aboard a United Launch Alliance Atlas V 401 rocket built by Lockheed Martin.