Nasa's Curiosity rover has detected organic molecules on Mars, including five never before seen on the red planet, in a dried lakebed near the equator. The compounds, preserved for an estimated 3.5 billion years, are considered building blocks for life on Earth, but their origin remains uncertain.
Scientists cannot determine whether the molecules are remnants of ancient Martian life, delivered by meteorites, or formed through geological processes. 'Is it life? We can't tell, based on this information,' said Prof Amy Williams, an astrogeologist at the University of Florida and a Curiosity mission scientist who led the experiment.
The rover, which landed in 2012, has been exploring the Gale crater and Mount Sharp. Despite harsh surface conditions with temperatures below -100°C at night and intense solar radiation, the findings suggest that organic matter can survive in the subsurface. 'It's really exciting to see that large complex material can survive,' Williams added.
Among the detected compounds were benzothiophene, a sulphurous chemical often delivered by meteorites, and a nitrogen-bearing organic compound with a structure similar to DNA precursors. However, Williams cautioned: 'It is definitely a building block to how DNA is made now. But it is truly just the bricks, not the house.'
The discovery bolsters hopes for the European Space Agency's delayed Rosalind Franklin mission, set to launch in 2028, which will drill deeper and perform more sophisticated tests to assess the origin of organic chemicals on Mars. The findings are published in Nature Communications.
