Curiosity piqued on Mars after discovery of mysterious organic material

8 Jun 2018

NASA’s Curiosity rover at the site where it reached down to drill into a rock target called ‘Buckskin’ on lower Mount Sharp. Image: NASA/JPL-Caltech/MSSS

We just took another massive step to one day finding direct evidence of ancient life on Mars after the Curiosity rover stumbled on ancient organic material.

Mars was once considered the land of little green beings who one day might visit us but, as we entered the space age, it became abundantly clear that nothing lives on the barren, desert planet.

However, in a discovery that could have major implications for our understanding of life itself, NASA has announced that its Curiosity rover has picked up a scent of ancient organic material preserved in rocks on Mars.

While it doesn’t necessarily confirm evidence for life having existed on the Red Planet, it does give us a new path of investigation for future rover and even crewed missions in the years to come.

Publishing its findings in Science, a NASA team revealed that the organic molecules were found in 3bn-year-old sedimentary rock near the planet’s surface and that there is an indication of seasonal variations in the levels of methane in the Martian atmosphere.

Typically, organic molecules contain carbon and hydrogen but also oxygen, nitrogen and other elements.

While commonly associated with life, organic molecules can also be created by non-biological processes and are not necessarily indicators of life.

“With these new findings, Mars is telling us to stay the course and keep searching for evidence of life,” said Thomas Zurbuchen, associate administrator for the Science Mission Directorate at NASA’s headquarters.

“I’m confident that our ongoing and planned missions will unlock even more breathtaking discoveries on the Red Planet.”

Seeing patterns of seasonal ‘breathing’

Despite this find, the source of the molecules remains a mystery, with no way of knowing yet whether it was created by an ancient life, or just existed independent of life.

However, there is sufficient optimism that it could be linked with life given that, over the past few years, Mars’ image of a dry planet has been challenged time and again by the discovery of evidence of both potential liquid water on Mars today, and large bodies of water in the planet’s distant past.

Meanwhile, the discovery of seasonal methane was confirmed over the course of nearly three Martian years – equivalent to six Earth years – with help from Curiosity.

Water-rock chemistry might have generated the methane, but scientists cannot rule out the possibility of biological origins, NASA said.

Methane previously had been detected in Mars’ atmosphere in large, unpredictable plumes, but this new result shows that low levels of methane within Gale Crater repeatedly peak in warm, summer months and drop in the winter every year.

“This is the first time we’ve seen something repeatable in the methane story, so it offers us a handle in understanding it,” said Chris Webster, lead author of the second paper.

“This is all possible because of Curiosity’s longevity. The long duration has allowed us to see the patterns in this seasonal ‘breathing’.”

Colm Gorey was a senior journalist with Silicon Republic