NASA has been taking a closer look at Mars as the rover Curiosity has trekked across the Red Planet. Now, though, a NASA orbiting spacecraft has revealed other clues about this planetary body. It's captured images of seasonal features that may show liquid water that exists on the Red Planet today.
The new features captured in the images are dark, finger-like markings that advance down some Martian slopes when temperatures rise. That's not all the researchers have for evidence, though. There are also corresponding seasonal changes in iron minerals on the same slopes. In addition, there's a survey of ground temperatures and other traits at active sites. Altogether, the new evidence supports the idea that brines with an iron-mineral antifreeze may flow seasonally.
These dark features are known as "recurring slope lineae," or RSL. So far, researchers have confirmed 13 RSL sites using images from the orbiter's Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument.
"We still don't have a smoking gun for existence of water in RSL, although we're not sure how this process would take place without water," said Lujendra Ojha, one of the researchers, in a news release.
So far, the researchers haven't found any spectral signature tied to water or salts. But they have found distinct and consistent spectral signatures of ferric and ferrous minerals at most of the sites. These iron-bearing minerals were more abundant or features distinct grain sizes in RSL related materials. This could mean that some kind of wet process is involved.
"The flow of water, even briny water, anywhere on Mars today would be a major discovery, impacting our understanding of present climate change on Mars and possibly indicating potential habitats for life near the surface on modern Mars," said Richard Zurek, Mars Reconnaissance Orbiter project scientist, in a news release.
