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Science and Innovations

NAU Scientist: Mysterious Mars Streaks Aren’t Liquid Water

NASA/JPL/University of Arizona

NASA announced a year ago mysterious dark streaks on Mars might be caused by liquid water. But a new study out of Northern Arizona University says those features are actually dry.

The streaks (called “recurring slope lineae”) appear seasonally on slopes of Mars and then vanish again.  Christopher Edwards of NAU’s astronomy department measured their temperature with an instrument on the Mars Odyssey orbiter.

Wet soil would heat and cool differently than the surrounding landscape. But Edwards found no temperature difference between the streaks and nearby areas.

That means the features can’t contain more than 3 percent water by weight. “So these features are as wet as the driest deserts on Earth, no more wet than that!” Edwards says. “And they are in fact entirely consistent with dry surface materials. So that was the big finding of this study.”

Edwards says scientists need to consider other processes that could create the seasonal streaks. 

The study appears in Geophysical Research Letters.

Melissa joined KNAU's team in 2015 to report on science, health, and the environment. Her work has appeared nationally on NPR and been featured on Science Friday. She grew up in Tucson, Arizona, where she fell in love with the ecology and geology of the Sonoran desert.
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