Aliens discovered on Mars? Don’t believe the hype
NASA’s Mars Curiosity rover, which has been exploring the Red Planet since 2012, has discovered organic molecules in Martian rocks and atmospheric methane levels that change seasonally, according to an announcement and a live discussion the space agency held on Thursday, June 7. Proof of alien life? Not so much.
The findings, which have been published in two separate papers in the journal Science, are not themselves evidence of present or past Martian life but do indicate a need for further study of Mars’s surface and subsurface, according to Thomas Zurbuchen, associate administrator of NASA’s Science Mission Directorate who works out of NASA’s Headquarters in Washington, D.C.
“With these new findings, Mars is telling us to stay the course and keep searching for evidence of life. I’m confident that our ongoing and planned missions will unlock even more breathtaking discoveries on the Red Planet,” Zurbuchen said.
The presence of organic compounds, which contain carbon and hydrogen and (possibly) oxygen, nitrogen, and other elements, in Martian rocks, suggests the planet could have supported life very early in its history.
Curiosity found the three billion-year-old organic compounds in sedimentary rocks near the Martian surface after drilling in four regions on Gale Crater.
Also known as mudstone, these sedimentary rocks formed several billion years ago from silt that once sat at the bottom of ancient lakes.
A suite of instruments on the rover known as the Sample Analysis at Mars (SAM) separated the organic materials from the rocks by heating collected samples to temperatures hotter than 900 degrees Fahrenheit (500 degrees Celsius). Under such heat, organics are released from powdered rocks.
SAM detected small organic molecules that are likely fragments of larger organic molecules that do not easily vaporize. It also detected sulfur, which could have assisted in preserving the organic molecules within the rocks.
These findings build on an earlier detection of organic molecules containing chlorine that was found by SAM in 2013 in rocks found at Gale Crater’s deepest point.
In its latest discovery, SAM measured concentrations of about ten parts per million or more of organic compounds, an amount similar to that detected in meteorites from the Red Planet. This level is about 100 times greater than any previous finding of organic compounds on the Martian surface.
The molecules that were part of Thursday’s announcement include benzene, toluene, thiophenes, and small carbon chains.
Jen Eigenbrode of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, the lead author of one of the Science papers, emphasized that the source of these organic molecules has not been found yet. The wrinkle in the search for past or present Martian life is the fact that these molecules can be produced both biologically and geologically processes.
“Curiosity has not determined the source of the organic molecules,” said Jen Eigenbrode of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who is lead author of one of the two new Science papers via an agency-issued release. “Whether it holds a record of ancient life, was food for life, or has existed in the absence of life, organic matter in Martian materials holds chemical clues to planetary conditions and processes.”
Given that radiation from space breaks down organic matter, discovering organic molecules in the top two inches (five centimeters) of Martian rock, which was likely deposited when the Red Planet was still habitable, is a good sign and indicates a need for deeper drilling, she said.
SAM is also responsible for the second major discovery announced, the detection of seasonal variations in the levels of methane found in Mars’s atmosphere over a period of nearly six Earth years, which translates to almost three Martian years.
Like the organic compounds found in Mars’s rocks, methane can be generated by either biological or geological processes. The latter includes water-rock chemistry. Previous studies of the Martian atmosphere had revealed large methane plumes that were difficult to predict. A post appearing on Universe Today noted that Mars has about one percent of the atmosphere that Earth does (at sea level), most of that is comprised of carbon dioxide.
The latest data confirms that the low levels of methane in Gale Crater increase during Martian summers and plummet during winters.
“This is the first time we’ve seen something repeatable in the methane story, so it offers us a handle in understanding it. This is all because of Curiosity‘s longevity. The long duration has allowed us to see the patterns in this seasonal ‘breathing,'” noted Chris Webster of NASA’s Jet Propulsion Laboratory (JPL) and lead author of the second Science paper.
Both discoveries are encouraging to scientists, who expect Mars’s next visitors, NASA’s Mars 2020 rover, and the European Space Agency‘s (ESA) ExoMars rover, to find additional organics both on the Red Planet’s surface and below it.
While not “proof of life on Mars” as some members of the media have alluded to – these recent findings have provided the scientific community with hope that life might, one day, be discovered on the fourth planet out from the Sun.
“Are there signs of life on Mars?” Michael Meyer, lead scientist for NASA’s Mars Exploration Program asked. “We don’t know, but these results tell us we are on the right track.”
Laurel Kornfeld is an amateur astronomer and freelance writer from Highland Park, NJ, who enjoys writing about astronomy and planetary science. She studied journalism at Douglass College, Rutgers University, and earned a Graduate Certificate of Science from Swinburne University’s Astronomy Online program. Her writings have been published online in The Atlantic, Astronomy magazine’s guest blog section, the UK Space Conference, the 2009 IAU General Assembly newspaper, The Space Reporter, and newsletters of various astronomy clubs. She is a member of the Cranford, NJ-based Amateur Astronomers, Inc. Especially interested in the outer solar system, Laurel gave a brief presentation at the 2008 Great Planet Debate held at the Johns Hopkins University Applied Physics Lab in Laurel, MD.