Water ice on Mars may create an environment friendly to life. Scientists have analyzed conditions beneath the ice sheets and found that in some regions of the Red Planet they would be sufficient to support life. The process that would enable microbes to survive can also be observed on Earth.
Life on Mars is a topic that captures the imagination of scientists and science fiction enthusiasts. We have not yet found any evidence that it ever developed on the Red Planet, but researchers are tirelessly searching for places where living organisms could survive. “Communications Earth & Environment” published an analysis indicating one promising environment.
Niche for life
Using mathematical modeling, the research team suggested that microorganisms could survive beneath the surface of water ice in the mid-latitudes of Mars. Ultraviolet radiation would be harmful to life on the surface, but a sufficiently thick surface can sufficiently stop it. Of course, the sheet could not be too thick, because then insufficient light would reach living organisms.
Another important factor is how dirty the ice is. Scientists calculated that heavily dusty ice sheets would block too much sunlight, but ice containing 0.01 to 0.1 percent dust at a depth of 5 to 38 centimeters could potentially contain a zone favorable to life. Dust particles within the ice can cause occasional, local melting at depths of up to about 1.5 meters, providing liquid water needed for photosynthesis.
As scientists explained, such structures can be observed, for example, on Mars' Terra Sirenum – the white edges of geological formations visible in the image below may be slightly dusty water ice.
The white edges of these gorges on Terra SirenumNASA/JPL-Caltech/University of Arizona
“A common phenomenon on Earth”
Similar processes occur on Earth. Cryoconites are sometimes formed in glacial ice – cavities formed where the ice is contaminated with dust. Darker ice absorbs more solar energy and melts faster, creating deepening pockets of liquid water. They can be an excellent environment for microorganisms. Sometimes thawing occurs under the ice layer, creating a closed niche filled with water.
“This is a common phenomenon on Earth,” explained study co-author Phil Christensen of Arizona State University. -Dense snow and ice can melt from the inside out, letting in sunlight to warm it like a greenhouse, rather than melting from the top down.
Experts stressed that the potential existence of life-supporting zones does not mean that life exists or ever existed on Mars. However, the discovery means that the few instances of exposed ice in the mid-latitudes of Mars may be important areas to focus future searches on.
Main photo source: NASA/JPL-Caltech/University of Arizona