How Sun steals Martian atmosphere

WASHINGTON - Mars is losing its atmosphere slowly, and it’s all because of the Sun, say scientists. It is using its own breath, the solar wind, and its radiation to rob Mars of its air - causing a once probably habitable planet to turn cold and hostile for life.

Features resembling dry riverbeds, and the discovery of minerals that form in the presence of water, indicate that Mars once had a thicker atmosphere and was warm enough for liquid water to flow on the surface.

It appears Mars has been cold and dry for billions of years, with an atmosphere so thin any liquid water on the surface quickly boils away while the sun’s ultraviolet radiation scours the ground.

“Mars can’t protect itself from the solar wind because it no longer has a shield, the planet’s global magnetic field is dead,” said Bruce Jakosky of the University of Colorado, Boulder.

The solar wind and the sun’s ultraviolet radiation turns the uncharged atoms and molecules in Mars’ upper atmosphere into electrically charged particles (ions). Once electrically charged, electric fields generated by the solar wind carry them away.

The electric field is produced by the motion of the charged, electrically conducting solar wind across the interplanetary, solar-produced magnetic field, the same dynamic generators use to produce electrical power.

There are other suspects - more than 20 ancient craters larger than 600 miles across that bombarded Mars a long time ago could have blasted large amounts of the Martian atmosphere into space.

Although huge Martian volcanoes that erupted could have replenished the Martian atmosphere by venting massive amounts of gas, without the protection of its magnetic shield, all that would have gone futile.

NASA’s MAVEN mission is now attempting to investigate what is responsible for the loss of the Martian atmosphere. NASA selected the MAVEN (Mars Atmosphere and Volatile Evolution Mission) on September 15, 2008.

“MAVEN will examine all known ways the sun is currently swiping the Martian atmosphere, and may discover new ones as well. It will also watch how the loss changes as solar activity changes over a year. Linking different loss rates to changes in solar activity will let us go back in time to estimate how quickly solar activity eroded the Martian atmosphere as the sun evolved,” said Joseph Grebowsky of NASA’s Goddard Space Flight Center in Greenbelt.

It can discover how much water has been lost to space by measuring hydrogen isotope ratios. MAVEN will also help determine how much Martian atmosphere has been lost over time by measuring the isotope ratios of other elements in the air, such as nitrogen, oxygen, and carbon. (ANI)