Lola Gayle,

It’s a question planetary scientists have asked for decades: “Where did Mars’ atmosphere go, and with it the water?”

On Thursday, NASA announced new findings by their Mars Atmosphere and Volatile Evolution (MAVEN) mission which reveal the solar wind is indeed to blame.

“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,” said John Grunsfeld, astronaut and associate administrator for the NASA Science Mission Directorate in Washington. “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.”

New measurements taken by MAVEN indicate that the solar wind strips away gas at a rate of about 100 grams (equivalent to roughly 1/4 pound) every second. The findings also reveal that the erosion of Mars’ atmosphere increases significantly during solar storms.

“Like the theft of a few coins from a cash register every day, the loss becomes significant over time,” said Bruce Jakosky, MAVEN principal investigator at the University of Colorado, Boulder. “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.”

The air up there. Get the full story about Mars’ atmosphere, water, aurorae and more.

Image Above: Artist’s rendering of a solar storm hitting Mars and stripping ions from the planet’s upper atmosphere. Credit: NASA/GSFC