Astronomy

Recent study, published in the July 17 issue of Nature, shows that vast regions of the ancient highlands of Mars, which cover about half the planet, contain clay minerals, which can form only in the presence of water. Volcanic lavas buried the clay-rich regions during subsequent, drier periods of the planet’s history, but impact craters later exposed them at thousands of locations across Mars. The data for the study derives from images taken by the Compact Reconnaissance Imaging Spectrometer for Mars, or CRISM, and other instruments on the NASA’s Mars Reconnaissance Orbiter.

Meanwhile, another study, published in the June 2 issue of Nature Geosciences, finds that the wet conditions on Mars persisted for a long time. Thousands to millions of years after the clays formed, a system of river channels eroded them out of the highlands and concentrated them in a delta where the river emptied into a crater lake slightly larger than California’s Lake Tahoe, approximately 25 miles in diameter. Now, the scientist turning the findings into a list of sites where future missions could land to look for organic chemistry and perhaps determine whether life ever existed on Mars!

In a color-enhanced image above, we can see the delta in a crater, named Jezero Crater, which once held a lake. Researchers report that ancient rivers ferried clay-like minerals (shown in green) into the lake, forming the delta. Clays tend to trap and preserve organic matter, making the delta a good place to look for signs of ancient life. (Picture credits: NASA/JPL/JHUAPL/MSSS/Brown University)

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