Martian life could be lying dormant beneath the surface of the Red Planet, waiting to be revived, new research suggests.
A team of scientists found that microbes sprang back to life after decades of inactivity in the driest desert on Earth. Their study was carried out in the Atacama Desert in Chile, parts of which go without rainfall for many years on end.
The desert landscape eerily resembles images of the surface of Mars sent home by visiting robotic landers and rovers such as Viking, Opportunity and Curiosity. It is the most similar place to Mars on our own planet.
The scientists studied the region to discover whether microbes in the extremely arid soil were original inhabitants or had been blown in by weather. They studied the microbial colony since 2015, using sterilised equipment to identify the different species of life in scoops of soil.
To their surprise, they saw the microbes burst back into life following a rare shower of rain. It showed that they had adapted to exist in the extremely hostile conditions. The team say their findings demonstrate that organisms could similarly be lying inactive but alive in the martian soil.
Leader of the study, published in the Proceedings of the National Academy of Sciences, was Washington State University planetary scientist Professor Dirk Schulze-Makuch.
He said: “Our research tell us that if life can persist in Earth’s driest environment, there is a good chance it could be hanging in there on Mars in a similar fashion.
“In the past researchers have found dying organisms near the surface and remnants of DNA but this is really the first time that anyone has been able to identify a persistent form of life living in the soil of the Atacama Desert.
“We believe these microbial communities can lay dormant for hundreds or even thousands of years, in conditions very similar to what you would find on a planet like Mars, and then come back to life when it rains.”
Schulze-Makuch told Skymania News: “The soil in the Atacama is very similar to Mars in respect to lack of moisture, high UV radiation rates and even similar geochemistry (e.g. presence of perchlorates and nitrates – the only desert on Earth that´s in that way similar to Martian soil).”
Mars is drier and colder than the Atacama, but studies have shown that Mars had oceans and lakes billions of years ago, offering a habitable environment.
Schulze-Makuch, who is returning to the Atacama to see how the microbes have been getting along, added: “We know there is water frozen in the Martian soil and recent research strongly suggests nightly snowfalls and other increased moisture events near the surface.
“If life ever evolved on Mars, our research suggests it could have found a subsurface niche beneath today’s severely hyper-arid surface.”
Though Mars is a similarly rocky planet to Earth, it lacks a magnetic field to deflect space weather. The surface is therefore bombarded with deadly radiation from the Sun and space.
Skymania News asked another member of the research team, astrobiologist Professor Lewis Dartnell, of the University of Westminster, London, how that might affect the potential for life on Mars.
He told us: “The environment in the Atacama is much like that of the martian surface – it is exceedingly dry, and the UV levels are very high too.
“Another major hazard for dormant life near the surface of Mars is bombardment with particle radiation from the cosmic rays – Mars no longer has either a magnetic field or a thick atmosphere.
“Life on Mars might need to be at least a few metres underground to survive that radiation for long periods.”
Schulze-Makuch told Skymania News: “The surface receives more radiation, but much of the hard radiation on Mars is still blocked from the thin atmosphere. Also, most microorganisms found in our study were at some depth (2-5 cm or 20-30 cm) and thus somewhat protected, especially the 20-30 cm depth which would apply to Mars as well.”
Another recent study has suggested that lava tubes on Mars could provide a habitat for life. It has even been suggested that life could have been brought to Earth from Mars.
Related: Skymania’s guide to Mars
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