Mars may have microbes frozen on its icy surfaces

A team of researchers recreated the conditions on Mars in the laboratory — and something remarkable emerged: in pure ice, more than 10% of the bacteria’s amino acids had survived.

If there is life on Mars (or if there was life a long time ago), it may not be buried in the planet’s rocky crust. Instead, it may be trapped in ice.

That’s the conclusion of a new study from researchers at NASA’s Goddard Space Flight Center and Penn State University, who recreated the freezing conditions and irradiated from Mars in a laboratory.

The results, published in September in the journal Astrobiologysuggest that amino acidsor even their own microbescan remain preserved in Martian ice for dozens of millions of years.

“Fifty million years is much older than the expected age of some current surface ice deposits on Mars,” he says. Christopher Houseprofessor of geosciences at Penn State and co-author of the study, cited by .

“This means that if there are bacteria near the surface of Mars, future missions can find them“, adds the researcher.

Simulate Mars

Mars has two polar caps permanent water ice and some dry ice, as well as some patches of ice both on the surface and underground.

Here on Earth, this ice would be an ideal candidate to harbor life. But on Mars, any life forms in the ice would be exposed to the devastating Martian conditions.

Led by Alexander PavlovNASA Goddard space scientist, the team suspended bacteria Escherichia coli in pure water icemimicking the permafrost that covers much of the Martian surface.

Other samples combined bacteria with minerals such as silicate rock and clay, typical of the soil of Mars.

The samples were then cooled to –51°C and exposed them to gamma radiation similar to what they would have endured on Mars in the last 50 million years.

When researchers analyzed the samples, something remarkable came up: on pure ice, more than 10% of the bacteria’s amino acids had survived.

In soil and clay mixtures, organic molecules degraded ten times faster. In other words, life on Mars may have more more likely to survive on ice than on land.

“It was surprising to discover that organic materials placed only on water ice are destroyed at a much slower rate than samples that contain water and soil,” Pavlov said.

Frozen Suspension

The discovery turns a long-established assumption on its head. For decades, scientists have focused their searches on Martian rocks and ancient sediments, hoping to find fossilized traces of microbes.

But Pavlov’s work suggests that these environments may be too chemically active. The research is directly based on this change in perspective.

“There is a lot of ice on Mars, but most of it is just below the surface” says House. “Future missions will need a large enough drill or powerful shovel to access it, similar to Phoenix’s design and capabilities.”

A probe Mars Phoenixwhich landed near the Martian Arctic Circle in 2008, was the first to discover subsurface water ice. But it lacked the instruments to detect life or complex organic compounds.

Pavlov’s study suggests that a follow-on mission equipped with advanced spectrometers — or even a sample return system — could have a real chance of find preserved biomolecules.

The concept of mission Mars Life Explorercurrently under analysis by NASA, may be the first to apply this strategy.

Beyond the Waist

The experiment also points outwards, towards the icy moons of the outer solar system. Pavlov’s team repeated their tests in conditions similar to those on Europa and Enceladus, the frozen satellites of Jupiter and Saturn.

The results were even more encouraging: Colder temperatures further delayed molecular decomposition, which bodes well for the mission Europa Clipper from NASA, currently on its way to Jupiter, which will begin close approaches in 2030.

“These results suggest that pure ice or ice-dominated regions are a ideal place to look for biological material recent,” said Pavlov.

For scientists like Pavlov, the discovery changes the odds on the ancient question of Martian life. Cosmic rays can sweep the planet’s surface, but the cold can be your greatest preserver.