Nasa’s Curiosity rover has detected organic molecules on Mars, including five compounds never before observed on the red planet. The discovery was made in a dried lakebed near the equator, where the rover identified chemicals widely considered building blocks for life on Earth.
The analysis cannot determine whether the organic compounds are linked to ancient life, delivered by meteorites, or formed through geological processes. However, the finding suggests that if microbial life once existed on Mars, chemical fingerprints could remain preserved. “We think we’re looking at organic matter that’s been preserved on Mars for 3.5bn years,” said Prof Amy Williams, an astrogeologist at the University of Florida and a Curiosity mission scientist.
The rover identified benzothiophene, a sulphurous chemical often delivered by meteorites, and hinted at a nitrogen-bearing compound similar to precursors to DNA. Williams noted that while these are building blocks, they could also be generated geologically. “It is definitely a building block to how DNA is made now. But it is truly just the bricks, not the house,” she said.
Mars’s harsh surface conditions, including extreme cold and intense radiation, were thought to degrade organic matter. The discovery shows that complex material can survive in the subsurface. “For a long time, we thought that all organic matter was going to be seriously degraded,” Williams added.
The findings, published in Nature Communications, boost hopes for the European Space Agency’s delayed Rosalind Franklin mission, scheduled for 2028, which will drill deeper and perform more sophisticated tests to assess the origin of organic compounds on Mars.
