Martian atmospheric condition has long been a debate from many scientists. However, just recently from a data collected by a mission launched last 2013 to investigate the upper Mars atmosphere reveals its clearer picture from its atmospheric history and how it evolved to geologically.
The findings from the data collected from Mars Atmospheric and Volatile Evolution (MAVEN) mission changed the course of Martian exploration. According to Professor Bruce Jakosky, from the University of Colorado, Boulder, and colleagues, the mission made a detailed variation of the abundance of two argon isotopes in Mar's atmosphere.
Jakosky said in his statement from ABC Science News that the team is focusing on argon, a noble gas that can form some compounds under extreme conditions. They found out that argon gas has not been reacting chemically with anything else so this means it can only be removed from the Mars atmosphere through a physical process called sputtering.
"In this process, ions which have been created in the Mars upper atmosphere, an extended corona of gas surrounding the planet, are grabbed or picked up by the solar wind and accelerated to high velocities," Professor Jakosky said. He also added that some of the picked-up ions are slammed back into the planet and collide with atmospheric gasses and knock them out into space.
Measurement data from the MAVEN spacecraft suggests that there are 66 percent of argon in Mars disappeared from the atmosphere since the planet's formation. Also, oxygen and carbon dioxide atoms disappeared during the sputtering.
NASA also concluded that the MAVEN exploration mission result reveals that solar wind and radiation were responsible for the most atmospheric loss on Mars, and the depletion of the atmosphere resulted in the current climate conditions of the red planet. Solar wind, a thin stream of electrically conducting gas are constantly blowing out from the surface of Mars.
"The geological evidence points to there have been liquid water overflowing on the surface of Mars in its early history, but something changed," Professor Bruce Jakosky said. "The best explanation is that Mars had a thicker atmosphere that trapped heat and warm the planet, but the thick atmosphere disappeared. Leaving the planet cold and dry. We thought that carbon dioxide is the best gas for this, but where did it go?" Jakosky added.
Microbial life on Mars could have existed at the surface early in Mars' history overflowing with water. But as the planet dried up and cooled down, any life could have been driven down, force into rare surface oases or just simply died out.
Other condition that professor Jakosky pointed out that there could have been a magnetic field in Mars history but it also disappeared and stripped down the atmosphere. The carbon dioxide that should be a greenhouse gas was picked up the solar wind, releasing it into space.
A panel of researchers led by NASA director of Planetary Science Division Dr. Jim Green proposed to build a magnetic shield to protect Mars' atmosphere from the solar wind. However, professor Jakosky debated that shutting off the low level of ongoing removal of gas would take literally billions of years to have even a small effect on the thickness of the atmosphere.
