NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) mission have discovered that solar wind plays a significant role in the process that seems to have changed the Martian climate from an early, warm and wet atmosphere that might have supported life to the raw, barren planet Mars is today.
MAVEN data have helped scientists to identify the rate at which the Martian atmosphere currently is leaking gas to space from solar wind stripping. The discoveries point out that the erosion of Mars’ atmosphere builds up significantly in the time of solar storms. The research results from the mission show up in the Nov. 5 issues of the journals Science and Geophysical Research Letters.
“The red planet appears to have had a dense atmosphere warm enough to hold liquid water, which is a crucial ingredient and element for life as we currently know it,” told John Grunsfeld, astronaut and associate administrator for the NASA Science Mission Directorate in Washington. “Figuring out what happened to the Mars atmosphere will tell us of the dynamics and evolution of any planetary atmosphere. Knowing what can make such changes to a planet’s environment from one that could host bacterial life at the surface to one that doesn’t is crucial to know, and is a general question that is being focused on in NASA’s journey to Mars.”
The loss becomes significant over time
MAVEN readings state that the solar wind strips away gas at around 100 grams ( about 1/4 pound) every second. “Like a person stealing little stuff every day, the loss becomes significant over time,” stated Bruce Jakosky, MAVEN principal investigator at the University of Colorado, Boulder. “We’ve confirmed that the atmospheric erosion rises quite a lot during those solar blasts, so we presume that the loss rate was much bigger billions of years ago when the sun was young and more unstable.”
Furthermore, a sequence of powerful solar storms hit Mars’ atmosphere in March 2015, and MAVEN discovered that the loss was accelerated. The mix of greater loss rates and increased solar winds in the past indicates that loss of atmosphere to space was likely the primary process in altering the Martian climate.
The solar wind is a surge of particles, generally, protons and electrons, coming from the sun’s atmosphere with the velocity of about one million miles per hour. The magnetic field transported by the solar wind as it sweeps past Mars can generate an electric field, just like a turbine on Earth is used to produce electricity. This electric field speeds up electrically charged gas atoms, called ions, in Mars’ upper atmosphere and hurls them into open space.
MAVEN has been studying how solar wind and ultraviolet light pushes away gas from of the top of the planet’s atmosphere. New discoveries show that the disaster is happening in three different sectors of the Red Planet:
Down the “tail,” where the solar particles flow behind Mars, over the Martian poles in a “polar plume,” and from a widespread cloud of gas around Mars. The research team concluded that almost 75 percent of the striped ions are from the tail region, and almost 25 percent are from the plume sector, with just a slight contribution from the cloud.
Ancient areas on Mars have signs of abundant water – with features looking like valleys carved by rivers and mineral deposits that only shape from the existence of liquid water. These discoveries have led researchers to believe that a long time ago, the atmosphere of Mars was much denser and hospitable enough to create rivers, lakes and maybe even seas of running water.
Not too long ago, scientists using NASA’s Mars Reconnaissance Orbiter detected the seasonal appearance of hydrated salts proving briny liquid water on Mars. Still, the current Martian atmosphere is far too bleak and thin to hold long-lived or large amounts of running water on the planet’s surface.
Decisive mechanism for atmospheric loss
“Solar-wind erosion is a decisive mechanism for atmospheric loss, and was responsible for the significant shift of the Martian climate,” told Joe Grebowsky, MAVEN project researcher from NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “MAVEN also is researching other loss processes – such as loss due to collisions of ions or elusion of hydrogen atoms – and these will only increase the effect of atmospheric escape.”
The objective of NASA’s MAVEN mission is to figure out how much of the planet’s atmosphere and water has been driven off into space. It is the first such mission dedicated to figuring out how the sun might have affected atmospheric alterations on the Red Planet.