Overlooked Evidence From Viking Landers Shows 'Life May Still Exist' on Mars
Sometimes we fail to notice an important detail, even when it's right in front of us. Scientists are aware of how the slightest lapse in attention to detail or primitive methods of analysis can keep us from stumbling upon a momentous discovery.
In 1976, a pair of Viking landers combed the surface of Mars looking for signs of life. Among the findings in its data was the then momentous discovery that Mars contained trace evidence of water, organic molecules, and methane.
It's assumed that most of this material still exists on the red planet, as oxygen was found in Mars' atmosphere as recently as 2016.
Intrigued by the presence of these materials, researchers Gilbert V. Levin from Arizona State University and Patricia Ann Straat from the US National Institutes of Health decided to reexamine data from NASA's 1976 Mars Viking landings.
Of particular interest to the researchers were traces of ambiguous chemical signals (radioactive 14CO2 isotope) found in the Martian soil. While the common consensus for years has been that this soil showed no signs of biological processes beginning or ending, the researchers say those ambiguous chemical signals are enough to warrant a new investigation.
"It is concluded that extant life is a strong possibility, that abiotic interpretations of the LR data are not conclusive, and that, even setting our conclusion aside, biology should still be considered as an explanation for the LR experiment," the researchers wrote. "Because of possible contamination of Mars by terrestrial microbes after Viking, we note that the LR data are the only data we will ever have on biologically pristine Martian samples."
The original overview of those Viking landings suggests otherwise. "According to scientists, Mars is self-sterilizing," says NASA. "They believe the combination of solar ultraviolet radiation that saturates the surface, the extreme dryness of the soil and the oxidizing nature of the soil chemistry prevent the formation of living organisms in the Martian soil."
This conclusion was challenged last year, though, when a Russian study suggested that tiny microbes, able to outlast extreme radiation, offer proof that life has been capable of surviving on Mars for millions of years.
We'll likely revisit this topic with great attention again in 2020, when a NASA Mars mission brings the foreign materials back to Earth for direct observation. This will mark the first-ever time that Martian materials are analyzed on our home planet.
Here's to hoping that any discovery of intelligent life happens before those samples are brought back to Earth and not after, because we've all seen enough films to know what happens when we foolhardily invite Martians to our planet.