NASA’s scientists from the Ames Research Center in California travelled to the Atacama desert in Chile, the driest place on Earth, to discover more clues about Mars’ habitability.
By drilling into the parched soil to collect microbial samples the researchers aimed to learn more about the possibility of life below the surface of Mars.
Instead, the researchers were confronted with findings which could dash the hopes of UFO hunters around the globe.
The arid landscape of the Atacama desert most resembles the hostile surface of Mars due to its dryness and only a few millilitres of rain a decade.
Rather than find out microbial life can thrive in these extreme conditions, the researchers were faced with the realisation the arid planes of the Atacama are an absolute kill zone for life.
And the prospect of finding microbial life on Mars looks even worse because the Red Planet is between 100 to 1,000 times dryer than the driest regions of the Chilean desert.
But Mary Beth Wilhelm, an astrobiologist at Ames who co-published the findings this month in the journal Astrobiology, said the unfavourable results could still teach valuable lessons about Mars’ past.
She said: “Before we go to Mars, we can use the Atacama like a natural laboratory and, based on our results, adjust our expectations for what we might find when we get there.
“Knowing the surface of Mars today might be too dry for life to grow, but that traces of microbes can last for thousands of years helps us design better instruments to not only search for life on and under the planet’s surface, but to try and unlock the secrets of its distant past.”
On June 7 this year, NASA announced the discovery of organic material in Martian rock samples drilled out by the remote Curiosity rover.
Although the presence of the so-called “tough” molecules was not immediately recognised as evidence of past or present life on Mars, the discovery was a monumental step towards unlocking the planet’s ancient history.
At the time, Thomas Zurbuchen, the associate administrator for the Science Mission Directorate at NASA, said: “With these new findings, Mars is telling us to stay course and keep searching for evidence of life.”
But NASA’s scientists now fear conditions on Mars are too dire for life to thrive enough to propagate the species.
In the new study, the scientists wrote: “Together, our results point to minimal or no in situ microbial growth in the driest surface soils of the Atacama, and any metabolic activity is likely to be basal for cellular repair and maintenance only.
“Our data add to a growing body of evidence that the driest Atacama surface soils represent a threshold for long-term habitability.
“These results place constraints on the potential for extant life on the surface of Mars, which is 100 to 1000 times drier than the driest regions in the Atacama.”