Ice on Mars may have favorable conditions for life – 10/19/2024 – Science

Layers of ice with up to 0.1% of dust particles on Mars could provide conditions suitable for life on the Red Planet. He studies Published last Thursday (17) in the magazine Earth and Environment Communications.

According to research, the solar ultraviolet rays that reach the Martian soil are up to 30% more radioactive than those on Earth, due to the absence of the ozone layer, which would cause the deterioration of any living cell. But some of this rays can be absorbed by larger ice particles up to 50 cm below the surface.

Under these conditions, light called photosynthetically active radiation (PAR) can arrive, thus enabling photosynthetic activity, that is, of microorganisms that convert sunlight into energy.

Of course, life is still missing two crucial elements: the presence of liquid water – currently, only ice, dust and snow are found – and nutrients, such as carbohydrate molecules.

However, according to Aditya Koller, a researcher at NASA’s Jet Propulsion Laboratory (US space agency) and corresponding author of the study, the results could enable new research in search of such conditions on Martian soil.

“Based on our work, we believe that regions exposed to dust in mid-latitudes represent the most accessible places to search for life on Mars today. Therefore, we hope that our study will help us, and other researchers, plan and design studies to examine Martian soil in more detail.” “. Boundby email.

Scientists from the University of Arizona, the Department of Atmospheric Sciences at the University of Washington, and the Arctic and Alpine Research Institute at the University of Boulder in Colorado (USA) also collaborated on the study.

The study, which did not include actual samples of Martian soil, performed simulations of the PAR spectrum according to soil density (up to 700 cm, up to 40 cm, up to 6 cm) and particle thickness (fine snow, ice, and thick ice). Snow) and dust composition (0%, 0.01%, 0.1%). The ideal length for light photosynthetic activity has been estimated to be 0.7 micrometres (µm).

According to the models, when there was a concentration of 0.1% to 0.01% of dust and ice In a layer of thin ice or snow, the radioactive habitable zone was much larger than when there were no ice dust particles at all (0%).

This happens, according to the authors, because the dust moves this region to shallower depths, due to the presence of greater PAR (photosynthetically active radiation). At a concentration of 0.1%, this percentage increased by 25 times.

The situation is similar to structures called “cryoconites” on the frozen surfaces of Alaska, where a series of bacteria – particularly cyanobacteria – and other photosynthetic microorganisms live in tiny holes – where light reaches – beneath the ice sheet. But one difference is that these sites contain liquid water, which has not yet been found in Mars’ photosynthetically active layer.

Comparing the two environments, the authors say they believe small areas of ice with dust beneath a frozen layer are ideal places to search for life.

Khuller says it’s difficult Finding extraterrestrial life Without visiting these sites on the surface, as well as learning about signs of life that may be different from those on Earth.

“I’ve been collaborating with a team of scientists to develop improved simulations of whether, where, and when dusty ice on Mars might melt,” he says. “In addition, we are recreating some of these scenarios in a laboratory setting to examine them in more detail.” researcher.

Claudia Lage, Professor and Head of the Laboratory of Radiation Biology at the Carlos Chagas Filho Institute of Biophysics, UFRJ (Federal University of Rio de Janeiro), commented on the study upon request for the report. According to her, the research provides a new model for evaluating life in icy areas on Martian soil.

“The model built in the article is very interesting in focusing on the icy regions of the planet, where water (in the form of snow or ice) has an effective absorption capacity for high-energy UV radiation, although it allows photosynthetic light to reach subsurface regions.” “Right where there could be some form of life.”

When asked if further research in similar areas could help clarify the possibility of extraterrestrial life, Lage says yes, they are interesting areas, although the ultraviolet rays in the planet’s most exposed soils make it possible for life to exist. Not practical at the moment.

“The best terrestrial counterpart is the frozen regions of Antarctica, where ice layers are able to protect this photosynthetic microbiome from the high levels of radiation in summer in that region,” the professor adds. “When we think about microbial life, all possible survival strategies exist in this group that is able to live in the most unimaginable environments on Earth, and why not, off Earth?”