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In a news conference today, NASA announced discoveries that provide additional evidence of seasonal water flows on Mars. Using data collected by the Mars Reconnaissance Orbiter, the MRO team presented images of dark lines that form on slopes during the martian spring/summer and fade in winter.
During the news conference, HIRISE principal investigator Alfred McEwen (University of Arizona), discussed that these “finger-like” features were found in Mars’ mid-southern latitudes. “The best explanation for these observations so far is the flow of briny water,” he said.
McEwen based his explanation on several key facts: First, salt lowers the freezing point of water (“plain” water would simply stay frozen on Mars) Secondly, the temperature on Mars during these flows ranges from -23 to +27 degrees Celsius, which rules out CO2. While there is significant evidence of flowing water, the team did state that there is no direct detection of water since it evaporates quickly on Mars.
Regarding the dark color of the flows, McEwen added, “The flows are not dark because of being wet, they are dark for some other reason.” McEwen also mentioned that researchers will need to re-create Mars-like conditions in the lab to better understand these flows, stating, “It’s a mystery now, but I think it’s a solvable mystery with further observations and laboratory experiments.”
MRO Project Scientist Richard Zurek (JPL) offered his thoughts as well. ”These dark lineations are different from other types of features on Martian slopes,” he said, “and repeated observations show they extend ever farther downhill with time during the warm season.”
What also proves intriguing to the team is that while gullies are very abundant on colder slopes that face the poles, the dark flows discussed in today’s news conference are found on warmer slopes which face the equator.
During the conference, Philip Christensen (Arizona State University) presented a map showing concentrations of “salts” in the same locations that the dark, “finger-like” flows were found.
McEwen reiterated during the Q&A session that the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), hasn’t detected any signs of water and that laboratory simulations will be necessary to gain a better understanding of these features – basically the team is seeing signs of flowing water, but not the water itself.
If you’d like to learn more about the Mars Reconnaissance Orbiter and today’s announcement, you can visit: http://www.nasa.gov/mro
To see more images related to the new findings, see this link from JPL.
Sources: NASA/JPL News Conference, NASA/JPL News