Even while the Mars rover Curiosity continues to discover the secrets of Martian water billions of years ago, a somewhat unsung hero silently orbits the planet searching for clues on why that water disappeared over time. The MAVEN orbiter, short for Mars Atmosphere and Volatile Evolution, continues to sample and analyze the tenuous atmosphere of the red planet in order to solve the mystery of its thinning atmosphere, that will eventually lead to more clues as to what befell this planet that could have very well supported organic life in the past.
Curiosity’s findings supported theories that the Gale Crater was once a vast and deep lake at one point in time billions of years ago. To have that amount of water, however, Mars needed to have an atmosphere thick enough for support the usual water cycle and to prevent water from escaping. But water did vanish eventually. In theory, this was due to the fact that Mars’ own atmosphere was disappearing as well, until it could no longer keep water on the planet as well.
Utilizing data from its Solar Wind Ion Analyzer or SWIA, MAVEN traversed Mars’ ionosphere in search for clues There, it discovered that streams of solar winds actually penetrated the ionosphere, which is usually the first line of defense against such particles, and lower layers of the atmosphere, charging the molecules there and aiding in their escape from the planet’s gravitational pull. MAVEN’s Suprathermal and Thermal Ion Composition or STATIC, on the other hand, observed plumes of charged particles escaping the planet’s hold. Indeed, solar winds seem to be the culprit here, but it is only half the answer and only the trigger.
The Earth, which also has its own ionosphere and is hit by solar winds as well, has another line of defense. Magnetic fields carry charged particles from the solar winds to the poles of the earth, which then manifest themselves as the popular Aurora Borealis and Aurora Australis. These magnetic fields are produced by the churning of liquid metals in the hot core of the earth. Mars, unfortunately, is no longer a warm body. Its center has cooled off long ago and no longer has a magnetic field to help fend off solar winds. Its smaller size also produces a weaker gravitational pull that would have helped keep its atmosphere in place longer.
While these latest clues help paint a better picture of Mars’ “death”, it isn’t the complete picture just yet. The questions of how and why aren’t sufficiently answered and NASA‘s Martian robots will continue to plow the land and sail the skies until those answers have been found, more or less.
VIA: Ars Technica