Much Ado About Martian Organics

James Marshall
June 8, 2018

The nuclear-powered rover has detected a variety of organic compounds, a requirement for life as it's known on Earth, in three-billion-year-old rocks deposited on the floor of Gale Crater.

The Curiosity rover has lasted three times as long as it was meant to and is still going, which helped with the study of seasonal methane cycles. Combined, these results present tantalising hints of a potentially habitable Martian past.

Questions remain, however, as to how the organic material was formed. "While we don't know the source of the material, the incredible consistency of the results makes me think we have a slam-dunk signal for organics on Mars", Eigenbrode said. "It had the ability to support life-but doesn't mean life were there". Now, scientists working with NASA's Curiosity rover are reporting that this rock still harbours organic molecules that must have been present in the water all those eons ago. Part of its duties include sampling the dirt and the atmosphere for interesting molecules, like those that may reveal a history of life or habitability.

NASA has scheduled a live discussion for 2 p.m. ET focusing on "new science results" from the rover, although the nature of what has been found remains to be seen as no details will be made public before then.

However, there are several other ways the molecules could have ended up on the lake bed. They are fairly certain that it comes from melting water-based crystals, called clathrates, buried just below the planet's surface.

"With these new findings, Mars is telling us to stay the course and keep searching for evidence of life", Thomas Zurbuchen, NASA science director at agency headquarters, said in a statement.

Nasa's Curiosity rover has discovered organic matter on Mars, the agency has announced in a press conference.

The most exciting news is that the changes definitely match the Martian seasons, hitting a peak at the end of summer in the northern hemisphere. The carbon-containing gas is significant because most methane on Earth is produced by methanogen microbes, which are common in oxygen-poor environments. The molecules could be the remnants of past organisms, the result of chemical reactions with rocks or simply space debris. Combined with high-energy ultraviolet light and cosmic rays streaming in from space, perchlorates would destroy any organic material on the surface, leaving little to be seen by carbon-seeking landers and rovers. But for now, there's no evidence for any such bacteria.

Meanwhile, the scientists hope that the newly discovered methane cycle could lead them to understand where the gas originates and if it is a sign of life.

"We've been able to rule out some of the more simple or accepted ideas of Mars's methane", Dr Webster said.

In any case, Webster said the methane apparently works its way into the atmosphere from sub-surface reservoirs of some sort, places where non-biological geochemistry is going on or where microbial life might somehow flourish. This latest discovery adds evidence that Mars may have been capable of supporting life in its ancient past, though there's still no evidence that life had actually existed on the Red Planet. Plus, scientists don't know what the original molecules were before Curiosity heated the rocks to take the measurement, Utrecht University scientist Inge Loes ten Kate, who was not involved with the research, told Gizmodo.

There's so much left to learn about Mars. The rock samples were analyzed by SAM, which uses an oven to heat the samples (in excess of 900 degrees Fahrenheit, or 500 degrees Celsius) to release organic molecules from the powdered rock. Mars doesn't recycle its rock the way that Earth does-maybe its ancient dust can teach us a thing or two about our own planet's history, said Siebach.

Other reports by Click Lancashire

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