On Earth, solar radiation can travel up to several meters into the ice, depending on its optical properties. Organisms in the ice can harness the energy from photosynthetically active radiation while being protected from harmful ultraviolet radiation. On Mars, there is no effective ozone shield, so about 30% more harmful ultraviolet radiation reaches the surface compared to Earth. However, a new study shows that despite strong surface UV radiation, mid-latitude ice on Mars contains 0.01-0.1% dust, ranging from a few centimeters deep to several centimeters deep. It has been shown that a radioactive habitable zone exists with a range of up to 3000 m. Cleaner ice.
The white edges along these canyons on Mars' Terra Sirenum are thought to be dusty water ice. cooler others. It is thought that melt water could form beneath the surface of this type of ice, providing a potential site for photosynthesis. Image credit: NASA / JPL-Caltech / University of Arizona.
“Today, if we are trying to find life anywhere in the universe, the icy outcrops on Mars are probably one of the most accessible places we should look,” said a researcher at NASA's Jet Propulsion Laboratory. said Dr. Aditya Kuler.
Mars has two types of ice: frozen water and frozen carbon dioxide.
Dr. Cooler and his colleagues investigated water ice. The ice masses were formed from snow mixed with dust that fell on Mars during a series of ice ages over the past million years.
That ancient snow has since solidified into ice and is still dusted with dust.
Dust particles can block light in deeper layers of ice, but they are the key to explaining how underground pools of water form within the ice when exposed to the sun.
The black dust absorbs more sunlight than the surrounding ice, causing the ice to warm and potentially melt several feet below the surface.
Mars scientists are divided on whether ice actually melts when exposed to the Martian surface.
It's thought to be caused by the planet's thin, dry atmosphere, where water ice sublimates and turns directly into gas, similar to dry ice on Earth.
But the atmospheric effects that make melting difficult on Mars' surface don't apply beneath the surface of dusty snowpack and glaciers.
On Earth, dust in ice can create what are called cryoconite holes. This is a small cavity that forms in the ice when windblown dust particles (called cryoconite) land there, absorb sunlight, and melt deep into the ice each summer. is.
Eventually, these dust particles stop sinking as they move away from the sun's rays, but they still generate enough heat to create pockets of melted water around them.
This pocket can foster a thriving ecosystem of simple organisms.
“This is a common phenomenon on Earth,” says Arizona State University researcher Phil Christensen.
“Rather than melting from the top down, thick snow and ice melts from the inside out, letting in sunlight that warms it like a greenhouse.”
In 2021, the authors discovered powdery water ice exposed inside canyons on Mars and proposed that many canyons on Mars are formed by erosion as ice melts into liquid water.
Their new paper suggests that powdery ice lets in enough light for photosynthesis to occur as deep as 3 meters (9 feet) below the surface.
In this scenario, the upper layer of ice prevents shallow underground pools of water from evaporating, while also protecting them from harmful radiation.
This is important because, unlike Earth, Mars does not have a protective magnetic field to protect it from both the Sun and radioactive cosmic ray particles flying through space.
“Water ice most likely to form underground pools would exist in tropical regions of Mars between 30 and 60 degrees latitude, in both the northern and southern hemispheres,” the researchers said.
of paper appear in the diary Communication Earth and Environment.
_____
AR cruller others. 2024. Possibility of photosynthesis on Mars in snow and ice. common global environment 5,583;doi: 10.1038/s43247-024-01730-y
This article is a version of a press release provided by NASA.
Source: www.sci.news
