Mars was once an Earth-like planet but it was transformed from a world that could have supported life into the frigid desert place we know of today.
New data offered hints what transformed Mars into an arid world and why the Red Planet no longer has the ideal conditions to support life.
Martian Atmosphere
Liquid water, which is considered essential for life, may have once flowed on Mars as suggested by features on the Martian surface that resemble dry riverbeds and minerals that can only form when there is liquid water.
These features also indicate that the climate on the planet was much different before. It may have been warm enough to allow water to flow for extended periods of time. Water, however, is not stable on present day Mars and the problem lies with the planet's atmosphere being too cold and thin.
Researchers said that it is the planet's thinner atmosphere that prevents liquid water to thrive on the Red Planet. With thin air, water on Mars easily boils.
"Our results tell us that the thicker atmosphere that provided the heating that allowed water to be present was lost to space. That is, the thick atmosphere was stripped away by the sun and solar wind, and the thinning of the atmosphere caused the cooling of the planet that diminished the ability of liquid water to exist," planetary scientist Bruce Jakosky, of the University of Colorado Boulder, explained.
Carbon Dioxide On Mars Atmosphere Provide Necessary Ingredient For Life
Mars' atmosphere is primarily composed of carbon dioxide, an efficient greenhouse gas capable of heating and warming the planet.
Jakosky said that the loss of carbon dioxide from Mars may provide information why the surface of the planet could have gone from habitable eons ago to not being able to support life as we know it today. The thick carbon dioxide atmosphere would have allowed water and as a result, life to exist on the surface. The abundance and availability of carbon dioxide would have also made carbon, a necessary ingredient of life, accessible to organisms.
Loss Of Martian Atmosphere
Several factors can explain why Mars lost some of its atmosphere, which is now 1 percent as dense as that of Earth at sea level. New data from MAVEN spacecraft, however, suggest that solar wind and radiation were responsible for most of the loss of the planet's atmosphere and the depletion was enough to transform the Martian climate into what it is today.
"The early Sun had far more intense ultraviolet radiation and solar wind, so atmospheric loss by these processes was likely much greater in Mars' history," NASA explained. "These processes may have been the dominant ones controlling the planet's climate and habitability."
MAVEN
The new data were from NASA's MAVEN spacecraft, which was launched in 2013 to study Earth's smaller neighbor. Among the mission goals include determining how the atmosphere and water on the surface of the Red Planet were lost over time.
Jakosky and colleagues published these findings in the journal Science on March 31.
