MAVEN Mission Reveals Speed of Solar Wind Stripping Martian Atmosphere

Posted on November 5, 2015

Data from NASA's Mars Atmosphere and Volatile Evolution (MAVEN) mission has revealed the speed at which solar winds are stripping away the Martian atmosphere. NASA scientists believe the process likely played a key role in helping Mars transition from an early, warm and wet environment to the cold, arid planet Mars is today.

The MAVEN data indicates the loss of gas from the Martian atmosphere into space significantly increases during solar storms. MAVEN measurements indicate that the solar wind strips away gas at a rate of about 100 grams (equivalent to roughly 1/4 pound) every second.

Bruce Jakosky, MAVEN principal investigator at the University of Colorado, Boulder, says in a statement, "Like the theft of a few coins from a cash register every day, the loss becomes significant over time. We've seen that the atmospheric erosion increases significantly during solar storms, so we think the loss rate was much higher billions of years ago when the sun was young and more active."

The solar wind is described as a stream of particles (mainly protons and electrons) that flows from the sun's atmosphere at a speed of about one million miles per hour. The magnetic field carried by the solar wind can generate an electric field as it flows past Mars. This electric field accelerates electrically charged gas atoms, called ions, in Mars' upper atmosphere and shoots them into space.

Joe Grebowsky, MAVEN project scientist from NASA's Goddard Space Flight Center, says, "Solar-wind erosion is an important mechanism for atmospheric loss, and was important enough to account for significant change in the Martian climate. MAVEN also is studying other loss processes -- such as loss due to impact of ions or escape of hydrogen atoms -- and these will only increase the importance of atmospheric escape."

Research papers on the MAVEN solar wind data was published in the journals, Science and Geophysical Research Letters.

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