The Red Planet has sprung a leak.
New research suggests that water can escape from the Martian environment way faster than previously thought, potentially answering the question of why Mars – once a lush planet of lakes and rain clouds – is now a dry and dusty land of sand dunes.
Reporting in the journal Science, a team of French researchers used data from the Trace Gas Orbiter, a collaborative mission between the European Space Agency (ESA) and Russia’s space agency Roscosmos, to discover that large amounts of water are being lifted up into the upper atmosphere of Mars. Seasonal changes also affect this process, with more water escaping to the upper atmosphere in the warm and stormy periods.
As per their models, portions of the Martian upper atmosphere are “supersaturated” with 10 to 100 times more water vapor than its temperature should theoretically allow.
Once here in the higher and colder altitudes, the water is blasted with ultra-violet (UV) rays from the Sun, which disassociate the water molecules into hydrogen and oxygen atoms. These atoms, not bound by the relatively low gravity of Mars, are then free to escape into space.
"Until now, scientists thought it took much longer (about several decades) for water to get high into the atmosphere and dissociate into hydrogen atoms. In truth, this mechanism takes much less time: a few days to a few weeks,” Franck Montmessin, study author and director of research at the LATMOS laboratory, told Business Insider.
Still, the Martian atmosphere is still relatively dry, holding around 10,000 times less water vapor than that of Earth. Almost all water on Mars today exists as solid ice, although there is evidence to suggest liquid salty water still flows intermittently on present-day Mars. A study in July 2018 even hinted there could be a large lake of liquid water deep beneath the Martian surface, perhaps similar to the lakes found beneath the ice of Antarctica and Greenland on Earth.
The prospect of large quantities of liquid water is especially enticing as it could serve as a potential habitat for microbial life. No proof has been found of past or present life on Mars, however, there’s a wealth of evidence to suggest that the surface of Mars once held substantial quantities of liquid water and may have been habitable for microorganisms. This new research helps to explain, at least in part, how Mars became the much drier planet we know today.