An eye-opening new study has suggested that life may still exist on Mars, hidden deep below the surface.
Scientists studied methanogens—microbes found in Earth’s deep and extreme environments similar to Mars’s subsurface—and combined their findings with Martian data on water, ice, and geological features to pinpoint a potential habitat for primitive lifeforms 4.3–8.8 km beneath the surface in Acidalia Planitia.
Their findings will encourage those hunting for life on Earth’s celestial neighbour at a time when NASA’s Perseverance rover is scouring the Jezero crater for clues.
Scientists are focusing on methanogens to explore potential life on Mars. Methanogens thrive in specific underground environments on Earth, but these habitats often prove challenging even here.
A report written by a team of University of Barcelona scientists led by Professor Andrea Butterini explained: “The cold Martian subsurface is likely an even harsher habitat for methanogens.”
Hence, studies suggested that if methanogens exist on Mars, they would likely be part of complex ecosystems, interacting with other microbial species, as they rarely form single-species communities on Earth, he pointed out.
Prof Butterini explained that the southern region of Acidalia Planitia stands out as a possible site to search for life, particularly for cold-adapted methanogens like Methanosarcinaceae or Methanomicrobiaceae, which could rely on interactions with bacteria-like organisms.
This area is rich in heat-producing radioactive elements, and water radiolysis – the splitting of water molecules due to radiation – might provide the energy needed for such life forms.
The report adds: “Our knowledge of Mars’s subsurface is advancing thanks to orbiters, landers and rovers, but critical gaps exist.
“To make substantial progress in identifying habitable niches in the subsurface of Mars, it will be essential to elucidate the availability of inorganic carbon in the subsurface and to determine more accurately the depth at which water is located and the porosity/fracturing of the regolith, as these factors directly affect the thermal gradients and the efficiency of water radiolysis.
“As a result, both our analysis (which builds upon recent advances in understanding Mars’s subsurface) and previous research more focused on its surface converge in identifying the southern of Acidalia Planitia as a promising target area for future missions in the search for extant life in Mars’ subsurface.”
Mars, the fourth planet from the Sun, has long fascinated scientists due to evidence suggesting it once had conditions conducive to life.
Billions of years ago, Mars is believed to have had a thick atmosphere, liquid water on its surface, and a warmer climate. Features such as dried riverbeds, lake basins, and sedimentary rock layers visible today point to a past when liquid water was abundant.
These conditions and essential elements like carbon and nitrogen suggest that Mars may have been hospitable to microbial life.
The theory of panspermia even posits that life on Earth could have originated from Mars, transported via meteorites ejected from the Martian surface by asteroid impacts. This idea arises because Mars and Earth share similarities in their early history, and Martian meteorites have been found to contain organic molecules.
Efforts to uncover evidence of past or present life on Mars are ongoing and multifaceted. NASA’s Perseverance rover is currently exploring the Jezero Crater, a former lakebed, to collect rock and soil samples that may contain biosignatures—chemical traces of past life.
Such samples will be returned to Earth in the 2030s for more detailed analysis. Similarly, the European Space Agency’s Rosalind Franklin rover, part of the ExoMars mission, is designed to drill below Mars’s surface, where potential life could be shielded from harsh radiation.
Scientists are also studying methane plumes detected in the Martian atmosphere, which biological processes could produce. Each discovery brings humanity closer to answering whether life ever existed – or still exists – on Mars.
