Thanks to the data provided by the Compact Reconnaissance Imaging Spectrometer for Mars (or CRISM) which sits aboard NASA‘s Mars Reconnaissance Orbiter, a group of researchers from Brown University have recently discovered deposits of glass within impact craters on Mars, which might provide the first signs of ancient extra-terrestrial life.
A study from last year, led by Peter Schultz, a Geologist at Brown, has found organic molecules and even plant matter entombed in a layer of impact glass that formed during an encounter with a meteorite some millions of years ago in Argentina.
Schultz suggested that similar processes might have also preserved signs of life on Mars, if it was present at the time of collision.
“The work done by Pete and others showed us that glasses are potentially important for preserving biosignatures. Knowing that, we wanted to go look for them on Mars and that’s what we did here,” said Kevin Cannon, a Ph.D. student at Brown and the lead author of the new research. “Before this paper no one had been able to definitively detect them on the surface.”
The possibility of these Martian glass deposits containing clues to past organic life is made slightly more likely by that fact that some of it was found atop a crater, called Hargraves, that’s located near the 650-kilometres-long Nili Fossae trough – an area rich in hydrothermal fractures that might have sustained life just below the planetary surface.
“If you had an impact that dug in and sampled that subsurface environment, it’s possible that some of it might be preserved in a glassy component,” said John Mustard, a Professor of Earth, Environmental and Planetary Sciences at Brown. “That makes this a pretty compelling place to go look around, and possibly return a sample.”
Since glass has a much weaker reflective signature than rock, identifying it from a distance is a very difficult task. In order to avoid interference from the chunks of mineral embedded in the glass, Cannon and his colleagues mixed together powders with a similar composition to Martian rocks and turned them into glass – this allowed them to measure its spectral signal.
With that part of the puzzle taken care of, the researchers then fed the signature into an algorithm, which picked out similar signals in the data streaming from the CRISM.
The Mars orbiter has been flying around the Red Planet ever since its arrival on March 10, 2006, with the primary goal of figuring out the length of water‘s presence on the planetary surface.
“This significant new detection of impact glass illustrates how we can continue to learn from the ongoing observations by this long-lived mission,” said Richard Zurek, MRO project scientist at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California.
Owing to the fact that the Nili Fosae is located near one of the proposed landing sites for the Mars 2020 mission, in which a new NASA rover will collect samples in the hopes of one day returning them to Earth, it might be that one day we’ll get a closer look at this tantalizing glass.
The study was published in the science journal Geology.