Does life exist below the icy surface of Mars?
10-18-2024

Does life exist below the icy surface of Mars?

Scientists have long entertained the question, “Is there life on Mars?” While there’s no concrete evidence yet, a recent NASA study has sparked new curiosity. The research suggests that the frozen water beneath the Martian surface could potentially host microbial life.

Potential for photosynthesis on Mars

Based on computer modeling, the scientists discovered that sunlight could penetrate the water ice, thereby enabling photosynthesis in the meltwater pools beneath the surface.

Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy for food.

On Earth, ice formations have been found teeming with algae, fungi, and cyanobacteria – all of which thrive on photosynthesis. Could Mars be home to similar lifeforms?

The research was led by Aditya Khuller, who is affiliated with NASA’s Jet Propulsion Laboratory (JPL) in Southern California.

“If we’re trying to find life anywhere in the universe today, Martian ice exposures are probably one of the most accessible places we should be looking,” said Khuller.

Life in Mars’ frozen water

With two kinds of ice on Mars – frozen water and frozen carbon dioxide – the scientists focused on water ice as a potential host of life.

The experts traced the origin of this ice back to ancient snow mixed with dust during Martian ice ages in the past million years. This snowy blend, now solidified into ice, continues to carry specks of dust.

Even though dust could potentially obscure light in the ice’s deeper layers, it holds the key to how subsurface pools of water could form within the ice when exposed to the Sun.

Just like a black shirt absorbs more sunlight than a white one, dark dust absorbs more sunlight than the surrounding ice. This could potentially warm up and melt the surrounding ice – even a few feet below the surface.

Thriving ecosystems for simple lifeforms

However, not all Mars scientists are on the same page about whether ice can actually melt when exposed to the Martian surface.

Challenges arise due to Mars’ thin, dry atmosphere, where water ice tends to sublimate – meaning it turns directly into gas, similar to our dry ice here on Earth. Yet, these atmospheric constraints wouldn’t hinder below the surface of a dusty snowpack or glacier.

Just like Earth’s cryoconite holes – small cavities in ice formed by particles of windblown dust, the same phenomena can be observed on Mars.

These dust particles, absorbing sunlight and melting into the ice, could potentially form pockets of meltwater, paving the way for thriving ecosystems for simple lifeforms.

“This is a common phenomenon on Earth,” said study co-author Phil Christensen of Arizona State University, referring to ice melting from within. “Dense snow and ice can melt from the inside out, letting in sunlight that warms it like a greenhouse, rather than melting from the top down.”

Can Mars’ climate support life?

Understanding the climatic conditions of Mars is crucial in assessing its capacity to support life. Mars experiences much colder temperatures than Earth, with an average surface temperature of roughly -80 degrees Fahrenheit (-62 degrees Celsius).

Such frigid conditions arise from its thin atmosphere, composed primarily of carbon dioxide, offering minimal insulation against the harsh cold.

However, variations in Mars’ axial tilt and orbit can lead to changes in climate, similar to Earth’s seasons but with more extreme shifts. This dynamic atmospheric behavior sparks curiosity about how these changes may influence ice stability and potential life-harboring environments.

Future Mars exploration

The quest to unravel Mars’ mysteries stands at the forefront of planetary exploration. Upcoming missions, such as NASA’s Mars Sample Return mission, aim to collect Martian rocks and soil for unprecedented analysis.

These samples could provide invaluable insights into Mars’ geology, climate history, and potential biosignatures – indicators of past or present life.

Additionally, advancing technologies like spaceborne instruments and robotic systems enable more precise and extensive studies of Martian terrains.

Prime targets for future research

Christensen and Khuller’s latest paper theorizes that dusty ice could permit enough light for photosynthesis even nine feet below the surface. This could shield subsurface pools of water from evaporating and protect against harmful radiation, given that Mars lacks a protective magnetic field like Earth’s.

Interestingly, the water ice most likely to form subsurface pools would exist in Mars‘ tropics – between 30 degrees and 60 degrees latitude, in both the northern and southern hemispheres.

Propelling this fascinating research further, Khuller plans to replicate some of Mars’ dusty ice in a lab.

Meanwhile, scientists worldwide are mapping out promising spots on Mars to search for shallow meltwater. These locations could be prime targets for future scientific endeavors, beckoning both human and robotic explorers.

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