Solar Wind From Younger Sun Likely Stripped Upper Martian Atmosphere

Summary: Bombarding solar wind from a younger sun likely stripped the upper Martian atmosphere, according to research published Nov. 6 in Science.

Artist’s rendering of solar storm striking Mars and stripping ions from upper Martian atmosphere: NASA/GSFC, Public Domain, via NASA

Bombardments by storming solar wind in March 2015 shot electrically charged gas atoms in the upper Martian atmosphere out into space in a déjà vu of Martian climate change billions of years ago, according to research published Nov. 6, 2015, in Science.

The solar wind that touches every planet in the solar system is a stream of charged particles flowing in all directions outward from the corona, the sun’s outer atmosphere, at a speed of about one million miles (1,609,344 kilometers) per hour. In a Martian orbit since Sept. 21, 2014, the space probe for NASA’s Maven (Mars Atmosphere and Volatile EvolutioN) mission measures a gas loss rate of about 100 grams, or roughly one-quarter pound, every second from solar wind barrages.

Bruce Jakosky, MAVEN principal investigator, lead author of Friday’s research article, and professor of geological sciences at the University of Colorado-Boulder, notes the impact of the gas loss rate: “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 active.”

Solar wind plunders the upper Martian atmosphere because Mars’ current magnetic fields are extremely weak. With spotty localized occurrences, stronger in the Southern Hemisphere than in the Northern, the Red Planet’s magnetic fields are perceived as fossil remnants of an extinct dynamo. Contrastingly, the Earth generates its powerful magnetic fields, which are 5,000 stronger than Mars’ flimsy fields, with an active dynamo of iron and nickel in its core that effectively deflects solar wind and protects the terrestrial atmosphere.

The thin atmosphere and low temperatures that characterize modern Mars are inhospitable to surface liquid water, which would either evaporate or freeze. In an introduction to Science’s Nov. 6 special issue featuring four MAVEN-based research articles, Bruce Jakosky notes the fine interplay among variables in the transition from the past’s seemingly life-supportive indicators to the present’s arid desolation: “Indeed, the more we learn about Mars, the more we see the connections between its interior, surface, and atmosphere. Answering questions about the potential for habitability, presence of water, and history of its climate requires understanding Mars as a connected system over time.”

On Nov. 5, Dr. Michael A. Meyers, lead scientist for NASA’s Mars Exploration Program, poetically and succinctly explained the erosion of the upper Martian atmosphere at a news briefing, entitled “Gone with the Solar Wind,” via NASA TV: “So to answer to the question ‘What happened to the Mars atmosphere?’ I’ll quote Bob Dylan: ‘The answer, my friend, is blowing in the wind.’”

artist's concept of NASA's MAVEN spacecraft orbiting Mars: NASA/GSFC via NASA Science Mars Exploration Program

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

solar storm hitting Mars: NASA/GSFC, Public Domain, via NASA @ http://www.nasa.gov/press-release/nasa-mission-reveals-speed-of-solar-wind-stripping-martian-atmosphere

artist's concept of NASA's MAVEN spacecraft orbiting Mars: NASA/GSFC via NASA Science Mars Exploration Program @ https://mars.nasa.gov/resources/8125/artists-concept-of-nasas-maven-spacecraft-orbiting-mars/

For further information:

Brown, Dwayne, et al. "NASA Mission Reveals Speed of Solar Wind Stripping Martian Atmosphere." NASA > Press Release. Nov. 5, 2015.
Available @ http://www.nasa.gov/press-release/nasa-mission-reveals-speed-of-solar-wind-stripping-martian-atmosphere

Carlisle, Camille M. "Mars Losing Gas to Solar Wind" Sky & Telescope > Astronomy News. Nov. 9, 2015.
Available @ http://www.skyandtelescope.com/astronomy-news/mars-losing-gas-to-solar-wind-0911201523/

Chang, Kenneth. "Mars' Atmosphere Stripped by Solar Storms, NASA Says." New York Times. Nov. 5, 2015.
Available @ http://www.nytimes.com/2015/11/06/science/space/mars-atmosphere-stripped-away-by-solar-storms-nasa-says.html?_r=0

Jakosky, Bruce M. "Maven Explores the Martian Upper Atmosphere." Science, vol. 350, issue 6261 (Nov. 6, 2015): 643-645.
Available @ http://science.sciencemag.org/content/350/6261/643

NASA‏ @NASA. "Mars is a cold & barren desert today. Solar wind striped away its atmosphere." Nov. 5, 2015.
Available @ https://twitter.com/NASA/status/662351129557118976

NASA Goddard. "NASA / Solar Wind Strips Martian Atmosphere." YouTube. Nov. 5, 2015.
Available @ https://www.youtube.com/watch?v=gX5JCYBZpcg