NASA's Mars Reconnaissance Orbiter (MRO) has detected deposits of impact glass on the Red Planet that may provide a fresh avenue for investigating the question of whether life ever existed there. The hope is that glass forged in the intense conditions created by an asteroid impact may have preserved microscopic signs of life, as it has here on Earth.
Detecting the signature of the glass deposits proved to be no small feat for the MRO, as the weak spectral signal from the glass is usually overwhelmed by the rock entombed inside it.
In order to make the orbiter's instruments more sensitive to detecting the relatively weak signal, Jack Mustard, deputy investigator of the MRO mission, placed a Martian rock substitute in a kiln and fired it in order to create an impact glass-like substance.
He then analyzed the spectral qualities of the glass and used an algorithm to pick out similar deposits on Mars. This resulted in the detection of several large glass deposits located at the central peaks of various Martian impact craters.
“The researchers’ analysis suggests glass deposits are relatively common impact features on Mars,” states Jim Green, director of NASA’s planetary science division. Green continues, “These areas could be targets for future exploration as our robotic scientific explorers pave the way on the journey to Mars with humans in the 2030s.”
Impact glass back on Earth has been found to be a surprisingly effective medium for preserving clues to life, such as organic molecules and even plant life. Such was the case for a glass deposit found at the site of an impact crater in Argentina, which is believed to have formed millions years ago.
Scientist Peter Schultz of Brown University, Ohio, who was responsible for discovering the preserved specimens of life in the Argentinian impact glass, believes that a similar phenomenon on Mars could provide clues to life having existed in the planet's ancient past. However, for organic molecules to be preserved, they must have existed at the location and time of the impact event.
One deposit of glass was found at the Hargraves crater near Nili Fossae trough, which happens to be in the proximity of one of the candidate landing sites for NASA's 2020 Mars rover. The discovery of the glass deposits may well inform the eventual landing site of the mission, which will collect samples from the Martian landscape for analysis and possible return to Earth.