Traces of ancient Martian life might endure for tens of millions of years deep within ice deposits, persisting even against cosmic radiation. This conclusion was reached by researchers from NASA and the University of Pennsylvania, who demonstrated through laboratory trials that ice offers substantially superior shielding for organic molecules compared to Martian soil. This finding was reported on February 25th in the journal Science Daily.
The investigators simulated conditions mirroring the Red Planet to ascertain if biological molecules could subsist in the Martian environment. In their experiments, E. coli bacterial amino acids encased in pure water ice withstood radiation equivalent to over 50 million years of cosmic exposure.
The scientists placed bacterial samples within ice and bombarded them with gamma radiation while maintaining a temperature around minus 60 degrees Fahrenheit, approximating conditions found in Mars’s icy regions. A subset of samples was also combined with minerals and clay-like materials typical of the Martian regolith. This comparative analysis revealed a critical disparity: over 10% of the amino acids remained intact in the pure ice, whereas organic compounds degraded roughly ten times quicker when mixed with soil simulants.
The authors attribute this protective effect to the physical characteristics of ice. In the solid icy medium, secondary particles created by radiation impact are effectively “frozen” in place, impeding their access to the organic molecules. Conversely, in the presence of minerals, a thin interface forms between the ice and the rock, which accelerates material degradation.
These outcomes necessitate a shift in focus for future life-detection missions. Whereas stones and sedimentary rocks were previously the primary targets, scientists now view drilling into areas of pure subsurface ice or permafrost as more promising avenues. The research also bears relevance for studying the icy moons of Jupiter and Saturn—Europa and Enceladus. At lower temperatures, the breakdown of organic molecules slows even further, boosting the likelihood of finding preserved biological signatures.
The researchers point out that much of Mars’s ice lies directly beneath the planet’s surface. Investigating this ice will require future spacecraft outfitted with drilling capabilities comparable to those of the Phoenix mission, which first confirmed the existence of ice in 2008. The study suggests that Martian icy deposits function as unique “time capsules,” capable of safeguarding chemical evidence of the planet’s potential ancient biosphere.
Science Daily reported on February 18th regarding the ongoing contraction of the Moon. It was specified that Earth’s satellite continues to shrink as its interior cools. According to researchers, this process causes stress to build up in the crust, leading to the formation of tectonic features.
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