Breaking Mars news: NASA's Curiosity rover has NOT found life on the red planet. What it HAS found is organic molecules and seasonal variations in the level of methane in the atmosphere, with more in summer and less in winter.
It’s tantalising. Let’s start with the methane: the findings, published this Friday in the journal Science, suggest a cycle of methane activity, and indicate a dynamic environment below the rover in the subsurface rock. Could it be microbes deep underground, clinging or even thriving in cold, dark, damp pores in the rock?
Other explanations are possible: methane can be created by geological activity, by the interaction of water and rocks in the subsurface. However, the 'cycle' of gas is another hint the red planet could be quietly alive.
Methane has been identified in the Martian atmosphere before, as early as the mid-2000s by ESA’s MarsExpress satellite, yet it hasn’t ever been seen to come and go in the same spot until now. "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 from NASA's Jet Propulsion Laboratory, the lead author of the paper.
The Curiosity science team has also announced that it has found what are referred to as 'organic molecules' in 3-billion-year-old sedimentary rocks near the surface. The term organic might make you think of muesli and yoghurt, but in science-speak it means complex molecules containing carbon and hydrogen.
Curiosity drilled down and found the evidence in the top five centimetres of rock, a surprise given that the surface of Mars is hammered by radiation from space, and over time the light would break down organic matter.
There are organic molecules all over the place in our solar system - some were found by Rosetta on comet 67P - and they can be created by non-biological processes, but the findings serve as further encouragement to the researchers investigating our planetary neighbour.
Curiosity is not actually at Mars to look directly for life, but was sent instead to look for ‘habitability’. By exploring Gale Crater it has shown clear evidence that Mars once had liquid water on its surface, and views of the red planet from orbiting spacecraft have charted a desert landscape that appears to have been swept and hewn into shape by powerful flows of water.
"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 Headquarters, in Washington. "I'm confident that our ongoing and planned missions will unlock even more breathtaking discoveries on the Red Planet.”
Looking for life
The race is on now to look directly for signs of life. The joint ESA-Roscosmos ExoMars mission could be the one to find it. Right now the first of its two spacecraft, the Trace Gas Orbiter, is circling high above the Martian surface and sniffing the atmosphere for methane and other interesting gases with a Belgian-led instrument. It is also photographing the surface in precision detail with a Swiss-built camera. Scientists will aim to pair up any trace gas readings with features in the landscape in order to understand more about where they’re coming from.
Looking forward, NASA is getting ready to send its Mars 2020 rover to the red planet, and the ESA-Roscosmos ExoMars 2020 rover will also head there at the same time. An Italian-built drill will probe two metres below the surface and hunt for evidence of life, now or in the past.
Most Mars scientists don’t expect to find microbes alive at those depths, but some do. There’s also the chance the rovers will dig up fossilised evidence of life. The reality is, nobody knows what’s down there, but keep a look out for more breaking Mars news in the next few months and years.