Updated | Scientists have probed massive deposits of ice just below the surface of Mars. As shallow as 3 feet deep, these huge sheets of ice can be over 300 feet thick and span a third of the planet's surface. The deposits, researchers hope, could one day support explorers on Mars.
Using NASA's Mars Reconnaissance Orbiter spacecraft, a team led by Colin Dundas at the U.S. Geological Survey, Flagstaff, Arizona, analyzed the surface of the red planet. Their results were published Thursday in Science.
By observing steep slopes called "scarps" across eight locations, scientists were able to pinpoint large quantities of ice unearthed by soil erosion. Although the presence of subsurface ice has been predicted before, this new review of its vertical structure has revealed information about the thickness, layering and purity.
Climate on Mars
Detailed images map steep cliffs of ice. The ice could shine a light on the history of the Martian climate. "The fractures and steep slopes indicate that the ice is cohesive and strong," the authors wrote. "The presence of banding and color variations suggest layers, possibly deposited with changes in the proportion of ice and dust under varying climate conditions.
"The ice deposits likely originated as snowfall...and have now compacted into massive, fractured and layered ice."
The ice could be relatively new, the researchers believe, because of a lack of craters on the surface. Big chunks of rock have fallen from the ice as it has retreated. This leads the team to believe the ice is slowly retreating.
The subsurface ice, the authors believe, could be even more extensive than their results show, as much could still be covered by deeper soil.
The great distance from Mars to Earth brings challenges for scientists. Our own planet, however, can lend a hand as a research model. Dundas explained to Newsweek: "It's not possible to directly observe ice at the scales of our study from Earth, but terrestrial polar regions are similar to Mars in some ways."
Future source of water
For future Mars explorers, information about ice will be key, the authors write. They will need to know how deep, strong and pure the ice is to make full use of the resource. One day, subsurface ice could be water for astronauts.
This article has been updated to include comment from Colin Dundas.
