The mystery of Martian water continues to deepen as a new study looks at seasonal flowing features within Valles Marineris on the Red Planet, the biggest canyon in the Solar System.
Researchers from the University of Arizona have detected many RSL, recurring slope lineae (the technical term for the water streaks), along the side of canyons in the equatorial region of Mars. These RSL are shown to be associated with water, and they might have caused small erosion episodes in the region.
"There are so many of them, it's hard to keep track. The occurrence of recurring slope lineae in these canyons is much more widespread than previously recognized," said lead author Matthew Chojnacki in a statement.
"As far as we can tell, this is the densest population of them on the planet, so if they are indeed associated with contemporary aqueous activity, that makes this canyon system an even more interesting area than it is just from the spectacular geology alone."
The paper, published in Journal of Geophysical Research Planets, has a surprising finding. If we have understood the composition of the RSL correctly, Mars must have between 100,000 and 1,000,000 meters cubed of liquid water just below the surface.
The white arrows indicate locations in this scene where numerous seasonal dark streaks, called "recurring slope lineae", have been identified in the area of Mars' Valles Marineris. NASA/JPL-Caltech/University of Arizona
If this is the case then Mars must have a widespread mechanism to recharge this cycle. The researchers suggest an interaction between salts and the water vapor in the atmosphere could be a potential explanation as these streaks are believed to be made of a sort of brine.
There’s enough water vapor on Mars to produce the RSL, but there’s no known process efficient enough to extract all that water. The researchers have even suggested that the flow features in Valles Marineris might not be water-based at all, or maybe they have less water than RSL in other regions.
"There do seem to be more ways atmosphere and surface interact in the canyons than in blander topography, such as clouds trailing out of the canyons and low-lying haze in the canyons," Chojnacki continued.
"Perhaps the atmosphere-surface interactions in this region are associated with the high abundance of recurring slope lineae. We can't rule that out, but a mechanism to make the connection is far from clear."
More observations will be taken by NASA's Mars Reconnaissance Orbiter, and laboratories on Earth are simulating how these streaks are formed.