- NASA’s Curiosity rover found seven organic compounds on Mars, five new to the planet
- The compounds were detected in a dried lakebed near Mars’ equator, some 3.5 billion years old
- It is unclear if the organics are from ancient life, meteorites, or geological processes
NASA's Curiosity rover has uncovered a range of organic molecules on Mars - some of the same kinds of chemicals that, on Earth, are considered the basic building blocks of life. The discovery comes from a new type of chemical experiment conducted directly on the Martian surface, marking a significant step forward in how scientists study the planet, Space.com reported.
The rover detected seven different organic compounds in a dried-up lakebed near Mars' equator, five of which had never been seen on the planet before. While it's unclear whether these organic compounds are linked to ancient life, were delivered by meteorites, or formed geologically, the discovery suggests that if life did exist on Mars, chemical signs of it could still be present today.
"We think we're looking at organic matter that's been preserved on Mars for 3.5 billion years. 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.
Since landing in 2012, Curiosity has been exploring Gale Crater and climbing the slopes of Mount Sharp. Today, Mars is an extreme environment where nighttime temperatures can plunge below -100°C, and with almost no atmosphere, the surface is exposed to intense solar radiation. But billions of years ago, the planet was very different, with flowing water and a thicker atmosphere that could have supported life.
As Andrew Coates from University College London points out, early Mars had many of the same conditions that allowed life to emerge on Earth. "There's no known reason why life couldn't have started there too," he noted.
However, one lingering question has been whether any chemical evidence from that ancient, potentially habitable period, roughly 3.7 to 4.1 billion years ago, could survive to this day.
"For a long time, we thought that all organic matter was going to be seriously degraded by that harsh radiation environment. It's really exciting to see that large complex material can survive in the subsurface environment," Prof. Amy Williams added.
Curiosity's latest analysis suggests that it can. Among the compounds identified were benzothiophene, a sulfur-containing molecule often linked to meteorites, and signs of a nitrogen-bearing compound with a structure similar to molecules that can lead to DNA.
"There are several steps between what we found and DNA. It is definitely a building block to how DNA is made now. But it is truly just the bricks, not the house. You can generate these molecules geologically. The same stuff that rained down on Mars from meteorites is what rained down on Earth, and it probably provided the building blocks for life as we know it on our planet," she added.
These findings are fueling anticipation for the Rosalind Franklin rover, part of the European Space Agency program, now scheduled for launch in 2028. Unlike Curiosity, this rover will be able to drill up to two metres beneath the surface, where organic material is better protected from radiation, and carry out more advanced tests to determine where these compounds came from.
