Mars was once a warm planet that could potentially harbour water and life on its surface, like Earth. But something changed about 3.6 billion years ago, and it lost most of its atmosphere.
A new study published in the journal Science reveals that more water vapour is accumulating in the upper atmosphere of Mars, allowing more of it to escape into space. Which mean, Mars is losing water much quicker than expected.
In the Martian upper atmosphere, sunlight splits the water molecules down into hydrogen and oxygen, which then pass from the thin atmosphere into space. Using the data from the Atmospheric Chemistry Suite on the ExoMars Trace Gas Orbiter, a NASA-ESA project, to suggest that the accumulation of unprecedented amounts of water vapour is occurring about 50 miles up from the Martian surface. The orbiter found that parts of the atmosphere contain anywhere between 10 to a hundred times more water vapour than the atmospheric temperature should allow.
The water vapour loss is even greater in the warmer seasons of the Red Planet when dust storms contribute to the evaporation. The researchers believe that the shift from a warm, wet planet to a cold desert is causing the rate of Mars’ desiccation to rise.
The good news, however, is that water vapour and clouds only represent a tiny fraction of the planet’s water reserve as most of it is locked up in polar and mid-latitudinal ice caps. The polar ice is well-known because NASA’s Mars Reconnaissance Orbiter and the Mars Odyssey Orbiter have imaged it. A recent study showed a map of water ice that could be just an inch below the dusty Martian surface in the northern hemisphere called Arcadia Planitia.
Next, researchers wish to learn more about the subsurface ice and if it varies across the Martian seasons. Moreover, multiple orbiters observing the Red Planet as well as spacecraft roving on its surface over the course of years continue to offer new ways to discover the hidden icy treasures on Mars.
