Mars ice could preserve traces of ancient life for 50 million years, study finds

Ancient Microbes May Still Be Frozen Beneath Mars Ice, Says Study (Image: Canva)

For centuries, Mars has puzzled scientists regarding the question of life below its frozen surface. New research now indicates that remnants of ancient microorganisms could still be trapped in Martian ice, enduring cosmic radiation for millions of years. The discovery provides new hope that the evidence of past life may still be buried just beneath the frozen surface of the planet.

Are ancient microbes still present on Mars?

Scientists simulated Martian environments in a lab with E. coli bacteria and pure water ice. The samples were frozen at minus 60 degrees Fahrenheit and exposed to radiation levels similar to those on Mars. Even after conditions equivalent to 50 million years of radiation, more than 10 per cent of amino acids remained intact.

“Fifty million years is far greater than the expected age for some current surface ice deposits on Mars,” said Christopher House of Penn State. “That means if there are bacteria near the surface of Mars, future missions can find it.”

The team discovered that samples mixed with Martian soil or rock degraded much faster. Pure ice acted like a shield, trapping harmful particles before they could damage organic fragments.

How does radiation affect organic material?
The study, led by Alexander Pavlov at NASA’s Goddard Space Flight Center, explored how radiation alters organic molecules in Martian-like environments. When radiation strikes ice mixed with minerals, it forms reactive radicals that move freely and destroy amino acids. In pure ice, these radicals freeze in place, reducing molecular damage.

“While in solid ice, harmful particles created by radiation get frozen in place and may not be able to reach organic compounds,” Pavlov said. The researchers found that clay minerals, such as montmorillonite, do not protect these molecules. Instead, they make things worse by allowing thin liquid layers to form, letting radiation spread more easily.

What makes Martian ice the best place to search?
Temperature played a major role in how fast amino acids decayed. At colder, Europa-like temperatures, molecules survived much longer than under warmer, Mars-like conditions. Higher temperatures allowed radiation to produce more mobile oxidants that quickly destroyed organic material.

Interestingly, water content also changed how molecules reacted. Earlier research suggested that more water increased decay, but the new study found that in pure ice, radicals cannot move easily. In minerals containing water, however, radicals travel through liquid-like layers, accelerating damage.

This explains why ice, even when exposed, remains a better long-term preserver than wet rock or soil.

What does this mean for Mars exploration?
The team compared their findings with data from icy moons like Europa and Enceladus. They found that extreme cold conditions on these moons slowed molecular decay, strengthening the case for NASA’s Europa Clipper mission, now en route to study Europa’s frozen shell and ocean.

On Mars, the 2008 Phoenix lander already confirmed near-surface ice. Future missions, scientists say, must use stronger drills to reach deeper layers untouched by radiation. “There is a lot of ice on Mars, but most of it is just below the surface,” House said. “Future missions need a large enough drill or a powerful scoop to access it.”

Could Mars still hold ancient life?
The research, published in the journal Astrobiology, suggests that if microbial life once existed on Mars, its chemical traces may still rest beneath the frost. Supported by NASA’s Planetary Science Division and Penn State researchers, the study concludes that pure ice can preserve organic matter for tens of millions of years.

To find life’s ancient fingerprints, scientists now believe they must search not in rock, but in ice — where time, radiation, and decay have failed to erase the story of a once-living world.