Chasing Streaks on Mars
Last year, Chevrier led a team of researchers who investigated the seasonal flows found on Martian slopes at mid-latitudes. The scientists modeled the behaviors of different brine mixtures to see if any could exhibit similar characteristics to what had been observed on Mars.
Chevrier and his colleagues found that calcium chloride did not immediately evaporate, and left behind some liquid that could create the types of streaks seen on the Red Planet.
Others have attempted to explain the seasonal markings with "non-liquid" solutions, such as wind patterns, but so far none have seemed plausible, McEwen said.
"So far, there aren’t any good dry hypotheses," he said. "There are some possibilities, and we keep them open as working hypotheses, but no one has been able to come up with a detailed model that makes sense."
While scientists have long viewed present-day Mars as a dry and dusty world, evidence abounds that water once flowed across much of the planet billions of years ago. Frozen water has been detected near the planet's surface at middle-to-high latitudes, but so far, no definitive evidence of liquid water has been found.
The new findings raise intriguing questions about the possibility of liquid water on present-day Mars, which has ties to the ongoing search for life on the Red Planet.
"It's certainly very surprising to me that this is happening on Mars today," McEwen said. "If it is water, that really changes our thinking of the planet's water cycle and habitability."
On Earth, life teems wherever liquid water is found, which means a wetter Mars could have tantalizing prospects for hosting extraterrestrial life.
"Earth is loaded with liquid water —it's a liquid water paradise," Chevrier said. "I'm not saying this means life is possible on Mars, but this is a good small step."
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