NASA’s Perseverance rover is shedding light on organic carbon found on Mars, fuelling the exploration of whether the planet once supported life. This research highlights the structure of organic carbon discovered in sedimentary rock, which may indicate past microbial activity.
Last year, the rover identified organic carbon in two distinct rocks named Cheyava Falls and Walhalla Glades, located approximately 330 feet (100 metres) apart in the Jezero Crater, an area believed to have hosted a lake billions of years ago. The organic carbon serves as a vital clue, representing the molecular backbone for all known living organisms, yet its presence alone does not confirm biological origins.
The mudstone in which this organic carbon was found dates back between 3.2 and 3.8 billion years, forming under a now-dry body of water. Images released by NASA reveal the Cheyava Falls rock, characterised by a fine-grained, rusty-red mudstone with unique ring-like features and dark specks, potentially indicative of microbial life on Earth.
Utilising Perseverance’s SHERLOC instrument, researchers conducted an in-depth analysis of a complex form of carbon known as macromolecular carbon. This type of carbon shows similarities to both biotic and abiotic processes observed on Earth, as well as to carbon found in meteorites. This is the first time macromolecular carbon has been observed in Jezero Crater’s mudstones.
According to Kyle Uckert, a planetary scientist at NASA’s Jet Propulsion Laboratory and co-leader of the study, “These findings indicate that the habitability of Mars and the availability of organic materials may have been widespread across the planet billions of years ago.” However, while these findings suggest ancient Mars had the necessary ingredients for life, they do not provide evidence of life itself.
Uckert further explained that the instruments aboard Perseverance cannot determine if the detected carbon arose from biological processes linked to microbial activity. He emphasised the need for returning samples to Earth for more advanced testing: “We need the return of these samples to Earth for more rigorous testing with higher sensitivity and higher resolution laboratory instruments.”
Mars, now a cold and barren world, may have had a more hospitable environment early in its history, characterised by a thicker atmosphere and warmer climate that allowed liquid water to exist on its surface. Scientists believe that Jezero Crater may have been home to an ancient lake, with river channels spilling into it, creating environments that could have supported microbial life.
The ongoing exploration of Jezero Crater is part of Perseverance’s mission to uncover the planet’s secrets. As Uckert poignantly noted, “The only place in the universe where we know life has emerged is Earth. If life is discovered on Mars, it could indicate that the emergence of life is not restricted to Earth, assuming the right conditions and ingredients are available, which would be a profound discovery.”
