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Will Mars glass reveal life signs?

NASA spacecraft discovered deposits of impact glass preserved in Martian craters, possibly preserving ancient signs of life.

Researchers have found deposits of impact glass (in green) preserved in Martian craters, including Alga Crater, shown here. Image credit: NASA/JPL-Caltech/JHUAPL/Univ. of Arizona

Researchers have found deposits of impact glass (in green) preserved in Martian craters, including Alga Crater, shown here. Image credit: NASA/JPL-Caltech/JHUAPL/Univ. of Arizona

NASA’s Mars Reconnaissance Orbiter (MRO) has detected deposits of glass in craters on Mars. This type of glass – known as ‘impact glass’ – is formed in the searing heat of a violent meteorite impact. Because the material around at the time of the impact might get sealed in the glass, researchers believe the glass deposits could provide evidence of possible past life on Mars. The research was published online in the journal Geology on June 5.

During the past few years, research has shown evidence about past life has been preserved in impact glass here on Earth. In a 2014 study, Brown University researchers found organic molecules and plant matter entombed in glass formed by an impact that occurred millions of years ago in Argentina. Scientists suggest that similar processes might preserve signs of life on Mars, if they were present at the time of an impact.

The current study, also by researchers at Brown, showed large glass deposits in several Martian crater central peaks, the craggy mounds that often form in the center 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.

Knowing that impact glass can preserve ancient signs of life – and now knowing that such deposits exist on the Martian surface today – opens up a potential new strategy in the search for ancient Martian life.

Jim Green is director of NASA’s planetary science division at the agency’s headquarters in Washington. Green said:

The researchers’ analysis suggests glass deposits are relatively common impact features on Mars. 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.

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One of the craters containing glass, called Hargraves, is near the Nili Fossae trough, a 400-mile-long (about 650-kilometer-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 soil and rock samples for possible return to Earth.

Nili Fossae trough is already of scientific interest because the crust in the region is thought to date back to when Mars was a much wetter planet. The region also is rife with what appear to be ancient hydrothermal fractures, warm vents that could have provided energy for life to thrive just beneath the surface.

Jack Mustard of Brown University is a paper co-author. Mustard said:

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.That makes this a pretty compelling place to go look around, and possibly return a sample.

Bottom line: NASA’s Mars Reconnaissance Orbiter (MRO) has detected deposits of impact glass in craters on Mars. Researchers believe the glass deposits could provide evidence of possible past life on Mars.

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