NASA's Mars Reconnaissance Orbiter (MRO) has spotted glass in the red planet's impact craters. It is possible that the glass, formed in the scorching heat of ancient impacts, could signal signs of life, according to NASA and NASA's Jet Propulsion Laboratory (JPL).
A 2014 study, which was led by scientist Peter Schultz of Brown University in Providence, R.I., discovered plant matter and organic molecules entombed in glass formed by an impact that occurred millions of years ago in Argentina.
Fellow Brown researchers Jack Mustard and Kevin Cannon, building on the previous research, detail their data about Martian impact glass in the online edition of journal Geology.
Mustard and Cannon demonstrated large glass deposits are present in numerous ancient, yet well-preserved, craters on Mars. In order to identify rock types and minerals remotely, the scientists measured the spectra of light reflected off the Mar?s surface. However, impact glass does not have a particularly strong spectral signal.
In the lab, Cannon mixed together powders with a similar composition of Martian rocks and fired them in an oven to form glass. Then, he measured the spectral signal from that glass.
As soon as Mustard had the signal from the laboratory glass, he used an algorithm to choose similar signals in data from MRO's Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), for which he is the deputy principal investigator.
The technique pinpointed deposits in numerous Martian crater central peaks, the rocky mounds that form in the middle of a crater during a large impact. The fact the deposits were found on central peaks is a good indicator that they have an impact origin.
One of the craters containing glass, named Hargraves, is close to Nili Fossae trough, which is a 400-mile long depression that stretches across the Martian surface. The region is one of the landing site contenders for NASA's Mars 2020 rover, a mission to cache rock and soil samples for possible return to Earth.