Salty Water Flows on Mars Today, Boosting Odds for Life
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| Dark narrow streaks called recurring slope lineae (RSL) emanate from the walls of Mars’ Garni crater in this image by NASA’s Mars Reconnaissance Orbiter. These RSL are up to a few hundred meters in length. They are thought to be formed by the flow of salty liquid water. |
Liquid water flows on Mars today, boosting the odds that life could exist on the Red Planet, a new study suggests.
The enigmatic dark streaks on Mars — called recurring slope lineae (RSL) — that appear seasonally on steep, relatively warm Martian slopes are likely caused by salty liquid water, researchers said.
"Liquid water is a key requirement for life on Earth," study lead author Lujendra Ojha, of the Georgia Institute of Technology in Atlanta, told Space.com via email. "The presence of liquid water on Mars' present-day surface therefore points to environment[s] that are more habitable than previously thought."
Ojha was part of the team that first discovered RSL in 2011, by studying images captured by the High Resolution Imaging Science Experiment (HiRISE) camera aboard NASA's Mars Reconnaissance Orbiter (MRO).
The enigmatic dark streaks on Mars — called recurring slope lineae (RSL) — that appear seasonally on steep, relatively warm Martian slopes are likely caused by salty liquid water, researchers said.
"Liquid water is a key requirement for life on Earth," study lead author Lujendra Ojha, of the Georgia Institute of Technology in Atlanta, told Space.com via email. "The presence of liquid water on Mars' present-day surface therefore points to environment[s] that are more habitable than previously thought."
Ojha was part of the team that first discovered RSL in 2011, by studying images captured by the High Resolution Imaging Science Experiment (HiRISE) camera aboard NASA's Mars Reconnaissance Orbiter (MRO).
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| These dark, narrow, 100 meter-long streaks (called recurring slope lineae) are flowing downhill on Mars, and are inferred to have been formed by contemporary flowing water. Recently, planetary scientists detected hydrated salts on these slopes at Hale crater, corroborating their original hypothesis that the streaks are indeed formed by liquid water. The blue color seen upslope of the dark streaks are thought not to be related to their formation, but instead are from the presence of the mineral pyroxene. |
Credit: NASA/JPL/University of Arizona
RSL occur in many different locations on Mars, from equatorial regions
up to the planet's middle latitudes. These streaks are just 1.6 feet to
16 feet (0.5 to 5 meters) wide, but they can extend for hundreds of
meters downslope.
RSL appear during warm weather but fade away when temperatures drop, leading many researchers to speculate that liquid water is involved in their formation. The new study, which was published online today (Sept. 28) in the journal Nature Geoscience, strongly supports that hypothesis, team members said.
Ojha and his colleagues scrutinized data gathered about four different RSL locations by another MRO instrument, the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM).
"Using this instrument, we can deduce the mineralogical makeup of surface materials on Mars," Ojha said. "What we found was that at times and places when we see biggest RSL on the surface of Mars, we also found spectral evidence for hydrated salts on the slopes where RSL form."
Hydrated salts precipitate from liquid water, so detecting them is a big deal — especially since circumstances make it unlikely that CRISM could spot RSL water directly. (CRISM observes the Red Planet at the driest time of the Martian day, about 3 p.m., when any liquid surface water would likely have evaporated, Ojha said.)
RSL appear during warm weather but fade away when temperatures drop, leading many researchers to speculate that liquid water is involved in their formation. The new study, which was published online today (Sept. 28) in the journal Nature Geoscience, strongly supports that hypothesis, team members said.
Ojha and his colleagues scrutinized data gathered about four different RSL locations by another MRO instrument, the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM).
"Using this instrument, we can deduce the mineralogical makeup of surface materials on Mars," Ojha said. "What we found was that at times and places when we see biggest RSL on the surface of Mars, we also found spectral evidence for hydrated salts on the slopes where RSL form."
Hydrated salts precipitate from liquid water, so detecting them is a big deal — especially since circumstances make it unlikely that CRISM could spot RSL water directly. (CRISM observes the Red Planet at the driest time of the Martian day, about 3 p.m., when any liquid surface water would likely have evaporated, Ojha said.)
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