A Martian rock bearing unusual ‘leopard spot’ patterns may be the most compelling evidence yet of ancient microbial life on the Red Planet, according to a landmark study led by NASA scientists. The rock was discovered by the Perseverance rover in July 2024 within the Jezero Crater – a region once home to rivers and lakes.
The markings, found on a rock formation dubbed Bright Angel, are composed of iron-rich minerals vivianite and greigite. On Earth, these minerals are typically formed by redox reactions – chemical processes often driven by microbes. Although alternative, non-biological explanations such as heat-driven reactions have been explored, researchers found no evidence to support them, leaving microbial activity as the leading hypothesis.
Professor Joel Hurowitz of Stony Brook University, who led the study, emphasised the significance of the patterns forming relatively late in Mars’s geological history – around 3.5 billion years ago – suggesting the planet may have been habitable for longer than previously believed.
Perseverance has collected a sample of the rock for future return to Earth as part of NASA’s Mars Sample Return mission. This mission, in collaboration with the European Space Agency, aims to bring Martian samples back for detailed lab analysis. Scientists will examine isotopic ratios of elements like iron, sulphur, and carbon, which could help determine whether life was once present.
However, the timeline for the mission remains uncertain. President Donald Trump’s administration has cut NASA’s planetary exploration budget, casting doubt over the mission’s future. Despite this, NASA remains committed to Mars exploration and is reviewing options for cost-effective sample return strategies.
Hurowitz remains optimistic, noting that even if the current mission faces delays, the findings from Bright Angel provide powerful motivation to continue the search for life on Mars. Should the patterns prove biological in origin, it would mark a profound discovery: that Earth is not the only planet where life has evolved.
