NASA’s MRO has been watching the Martian surface since 10 March 2006. Image credit: NASA/JPL
The search for signs of water on the Red Planet continues, but recent research has been dealt a blow with its analysis of Mars’ downhill, dark, surface streaks. By using NASA’s Mars Reconnaissance Orbiter (MRO) and its High Resolution Imaging Science Experiment (HiRISE) camera, scientists have presented strong evidence that these dark features are not due to subsurface flowing water, but instead granular flows.
MRO has continued to observe the ever-confusing seasonal dark streaks since their discovery in 2011, when scientists claimed they could be a source of enough water to support microbial life. The recent evidence from MRO has shown that the dark features exist only on slopes steep enough for dry grains to descend the way they do on faces of active dunes.
They seasonal behaviour of these dark features consists of extending gradually downhill in warm seasons, then they disappear in the winter and repeat this pattern the next year. Seeping water has shown this sort of geological behaviour on Earth, but how this occurs on the Martian surface is very unclear. The scientists who conducted the research have suggested that there ...