Life on Mars - Science Fiction, or Real-Life Science?

The concept of life on the Red Planet has long captured the interest of scientists and filmmakers alike, and with new discoveries and groundbreaking expeditions, this future may no longer just be a thing of fiction. Yet, beyond space discovery, biology would be the backbone for truly bringing this planet to life. So this poses the question: what science would it take for life to really be possible on Mars? Offering insight into this is NASA’s Perseverance rover, a crucial tool in the Mars Exploration Programme that’s examining life from land to water, addressing whether Mars craters have hosted life before - and whether they could again. 

Key biosignatures recorded by Perseverance - namely from the Martian rock Sapphire Canyon - have recently been studied and have suggested habitable conditions on one of Mars’ most promising and insightful craters, Jezero. This article aims to dissect Perseverance’s findings through the lens of the key earth systems - land, water and air - to assess the true potential for life on Mars in an interconnected way. 

A solid start 

The lithosphere encompasses the fundamental geological requirements for a liveable planet, providing fundamental habitats, essential chemical resources, and partaking in crucial ancient rock-water interactions, providing the backbone for water cycles and fundamental water bodies. Twenty-four diverse minerals have been identified in the Jezoro crater, characterised by their volcanic origin, but also their interactions with water. Perseverance’s x-ray features enabled the creation of a mineralogical archive, and these minerals revealed details of those key water-rock interactions. The older rocks studied closer to the crater floor bore signs of harsh, hot, acidic liquid interactions - while this doesn’t rule out possible habitability, these conditions are harsh and unfavourable, making it more unlikely. When looking at more neutral and cool waters, completely different possibilities are revealed. 

Possibilities are flowing 

The hydrosphere is another earth system fundamental for planet habitability, going beyond meeting the individual metabolic and nutrient requirements for any living organisms it hosts, but also playing crucial roles in regulating temperatures and weather through complex interactions with the atmosphere. Continuing to look at the Jezoro craters’ multiple episodes of water activity, more cooler, neutral waters in later episodes left behind further insightful minerals. While direct biological evidence is still absent, these conditions could be interpreted as more microbe friendly, increasing the chances for the flourishing of life within the crater. While the intricate interactions between the lithosphere and hydrosphere have been covered, one can’t speculate over life on Mars without taking into account the other entire life systems which play a fundamental role in not only supporting life, but allowing it to flourish. 

There must be something in the air 

Despite past interactions revealing that the geology and water on Mars once exhibited favourable conditions for life, the potential for life on Mars cannot be theorised comprehensively without looking at the atmosphere enveloping it all. Providing not only gases that sustain biological life, but working with both the litho- and the hydrosphere in order to regulate temperature, the climate and weather, the atmosphere is a key backbone for not just the complexity of life, but the existence of life at all. On Earth, the atmosphere is able to successfully sustain an abundant Earth biosphere due to its gas composition of primarily nitrogen - the key component for life’s complex proteins, DNAs and RNAs - followed by oxygen vital for respiration and combustion. Contrastingly, the thin and comparatively weaker Mars atmosphere, composed of predominantly carbon dioxide, lacks the ability to provide a stable habitat due to its periods of extreme freezing, leading to an inability for water to flow freely on the planet.

To conclude

After compiling the fascinating evidence of the elements currently on Mars, and comparing these to the speculated optimal conditions that would sustain life there, it’s safe to say that fully functioning Martian societies may be confined to our favourite sci-fi books and films for 

the time being. However, this is nothing to be disheartened by - paying attention to just how fine tuned the systems that enable planetary health are could influence how we look after the planet we are lucky enough to inhabit now. All of the processes discussed through this article that would need to be kept within set ranges to enable life on Mars, from the gases that keep us breathing and the systems that control the weather, also need to be kept within set ranges on Earth. While we may not be expanding our livable universe to Mars just yet, the Red Planet can serve as a symbol of how delicate and worthy-of-preserving our own Earth is.