In May, 2018, Mars witnessed one of its worst storms. Amid the chaos, plumes of dust erupted up from the planet’s surface, towering as high as 35 miles. The storm was so severe that it claimed the life of NASA’s Opportunity rover, smothered by a hazy darkness that blocked out its solar battery panel. The last signal received from Opportunity was on June 10, 2018. NASA’s Mars Reconnaissance Orbiter confirmed the death when it spotted its limp robotic body later that year.
But Opportunity’s life wasn’t in vain — observations from that fateful storm may finally answer the question of what, exactly, caused Mars’ surface water supply to dry up.
In a pair of papers, new data reveals that water vapor was trapped in the swirling frenzy of dust, hitching a ride up the tall towers — and meeting its demise.
The studies provide a possible explanation for how water may have escaped the Martian surface billions of years ago, and disappeared into space after being carried up by dust towers.
Dust-ups on the Red Planet
The Red Planet is no stranger to dust storms. They sweep over the surface every year, lasting weeks at a time. But every three Martian years — about five and a half Earth years — these storms grow into massive weather events that encircle the entire planet and block its surface from sunlight.
During these global storms, massive dust towers erupt all over Mars. The towers are huge: Near the surface, they cover an area the size of Rhode Island, before rapidly growing to the size of Nevada as they spew up into the air. At their tallest, they can stretch to 50 miles, according to NASA. As the dust settles after this explosive event, it forms a dense layer across vast expanses of the planet’s the surface.
“Normally the dust would fall down in a day or so. But during a global storm, dust towers are renewed continuously for weeks,” Nicholas Heavens, a researcher at Hampton University in Hampton, Virginia, and lead author of the first study, said in the statement.
Heavens’ team found that these dust towers act as “space elevators,” which transport water vapor, gases, and other materials all the way to Mars’ upper atmosphere. There, solar radiation disintegrates the water molecules into thin air.
Today, most of the water on Mars exists in the form of ice or vapor, although scientists believed that it may have flowed on the Red Planet at some point in the past. Scientists are homing in on one such lake bed as part of NASA’s Mars 2020 mission — partly in the hope of finding life.