The question of why Mars’ atmosphere is so thin, cold, and desolate may have been answered. NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) mission has discovered the process that appears to have played a role in transforming the planet’s climate to the cold and arid planet it is today.
Scientists believe that Mars once had an atmosphere as thick as or thicker than today’s Earth. With data from MAVEN, researchers are now able to determine the rate at which Mars’ atmosphere is currently being stripped of its gas by solar winds. The findings have revealed that the erosion of Mars’ atmosphere increases significantly during solar storms.
MAVEN Mission Briefing — Solar Wind Strips Martian Atmosphere:
John Grunsfeld, astronaut and associate administrator for the NASA Science Mission Directorate in Washington, said:
‘Mars appears to have had a thick atmosphere warm enough to support liquid water,
which is a key ingredient and medium for life as we currently know it.”
“Understanding what happened to the Mars’ atmosphere will inform our knowledge of the dynamics and evolution of any planetary atmosphere. Learning what can cause changes to a planet’s environment from one that could host microbes at the surface to one that doesn’t is important to know, and is a key question that is being addressed in NASA’s journey to Mars,” he added.
Watch While Solar Wind Strips Martian Atmosphere, by NASA Goddard:
The measurements taken from MAVEN show the solar wind strips away gas at a rate of about 100 grams (equivalent to roughly 1/4 pound) every second. Bruce Jakosky, MAVEN principal investigator at the University of Colorado, Boulder, said:
“Like the theft of a few coins from a cash register every day, the loss becomes significant over time.
‘We’ve seen that the atmospheric erosion increases significantly during solar storms,’
so we think the loss rate was much higher billions of years ago when the Sun was young and more active.”
In March 2015, a series of solar storms hit Mars’ atmosphere, with MAVEN finding that the loss was accelerated. The researchers suggest that with the combination of greater loss rates and an increase of solar storms in the past, the loss of Mars’ atmosphere to space was likely a major process in changing the Martian climate, NASA wrote in a statement.
NASA Reveals How Sun Stripped Away Mars’ Atmosphere, by GeoBeats News:
Solar winds are streams of particles made up of mainly protons and electrons that flow from the Sun, reaching speeds of nearly one million miles per hour. The winds also have a magnetic field; as they move past Mars, they can generate an electric field, similar to a how a turbine here on Earth is used to generate electricity. The electric field accelerates electrically charged gas atoms, called ions, in Mars’ upper atmosphere, and then shoots them into space, according to NASA.
NASA has been using MAVEN to study how solar wind and ultraviolet light strip gas off the top of the planet’s atmosphere. There are three regions where the loss is experienced: The tail (where the solar wind flows behind the planet), above the Mars poles in a “polar plume,” and from an extended cloud of gas surrounding Mars.
It has been determined that almost 75 percent of the escaping ions are coming from the tail region, with almost 25 percent from the plume region, and just a small contribution coming from the extended cloud.
Measuring Mars’ Atmospheric Loss, by NASA:
Joe Grebowsky, MAVEN project scientist from NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said: “Solar-wind erosion is an important mechanism for atmospheric loss, and was important enough to account for significant change in the Martian climate.”
“MAVEN also is studying other loss processes — such as loss due to impact of ions or escape of hydrogen atoms — and these will only increase the importance of atmospheric escape.”
MAVEN was launched in November 2013, with the mission of determining how much of Mars’ atmosphere and water had been lost to space. The mission is a first of its kind, and is dedicated to understanding how the Sun may have influenced atmospheric changes on the planet.