A new study suggests that beneath Mars’ icy surface, there might be hidden pools of meltwater capable of supporting life.
This discovery could point to some of the most accessible places to search for life on the Red Planet.
The findings were published in Communications Earth & Environment by a team led by Aditya Khuller from NASA’s Jet Propulsion Laboratory, who will soon join the University of Washington Applied Physics Laboratory.
Researchers have discovered that enough sunlight penetrates the layers of ice on Mars to allow photosynthesis to occur in shallow subsurface pools of meltwater.
On Earth, similar subsurface meltwater pools within ice host various life forms like algae, fungi, and microscopic cyanobacteria, all of which depend on sunlight for photosynthesis.
“If we want to find life beyond Earth, Martian ice is probably one of the most accessible places to start looking,” says Khuller.
Mars has two types of ice—frozen water and frozen carbon dioxide (dry ice).
This study focused on water ice, which formed over the past million years from ancient snowfalls mixed with dust. As the snow solidified into ice, tiny dust particles remained inside.
These dust particles are essential because they absorb more sunlight than the ice around them, causing the ice to warm up and melt in small areas below the surface.
One challenge to finding liquid water on Mars is the planet’s thin and dry atmosphere. The atmospheric conditions cause surface ice to sublimate—turning straight into gas without melting—like dry ice does on Earth.
However, scientists believe these subsurface meltwater pools could still exist beneath dusty ice layers, as they are protected from the harsh Martian environment.
The research team used computer models to show that dusty ice allows enough sunlight to pass through for photosynthesis to occur up to 10 feet (3 meters) below the surface.
In this scenario, the ice above the pools prevents them from evaporating and shields them from harmful radiation. Unlike Earth, Mars lacks a magnetic field, which leaves it vulnerable to ultraviolet rays and cosmic radiation. However, the ice could act as a protective barrier.
Scientists believe the most likely places to find these pools are between the latitudes of 30 and 60 degrees, in both Mars’ northern and southern hemispheres. These midlatitude regions could be promising targets for future human and robotic missions to explore.
“This study shows there’s a zone just below the ice surface where there’s enough light for photosynthesis and protection from ultraviolet rays,” says Steve Warren, coauthor and professor emeritus at the University of Washington. However, for life to survive, the ice in that zone must melt occasionally.
The team plans to continue their research by recreating Mars-like conditions in a lab. They also aim to map out potential locations for future exploration in the search for life.
This study opens up new possibilities in the quest to find life on Mars and guides where scientists should look next.
