NASA’s Curiosity rover and its mission to investigate whether Mars could have ever supported microbial life have taken one step closer to achieving its goal, with one of the most significant discoveries in the ongoing search for evidence of life on the Red Planet.
While exploring Gale Crater, NASA’s robotic rover uncovered a sample in 2020 and, using a chemical technique, determined that 21 carbon-based molecules were preserved in the clay-rich sedimentary rock. This also included seven that had never been identified on Mars before.
While the discovery does not definitively point to life on the Red Planet, it does strengthen the case that Mars has the chemical conditions to support life.
According to scientists, the most remarkable aspect of the discovery is not the molecules themselves, but their preservation
“The actual organic components they found are not strong evidence for life,” said Texas A&M University astrobiologist and geobiologist Dr. Michael Tice in a statement. Tice acknowledged that these compounds may also have evolved through abiotic processes, including formation in meteorites or other non-biological pathways.
“These organics were likely preserved in the rocks for a very long time, possibly billions of years, despite radiation and other harsh conditions on Mars,” Tice said.
“It blows my mind.”
Building Blocks of Life
Organic molecules are critical building blocks of life, but they can also form through non-biological processes, such as geological reactions or meteorite delivery. Similar preserved compounds on Earth help scientists study ancient environments, and their discovery on Mars provides new clues about the planet’s billion-year-old history.
“Studying how those compounds vary between different rocks can tell a story of how life and environments changed,” Tice recently said in a statement issued by Texas A&M. “Finding organics stored in similar ways on Mars tells us that there could be similar stories preserved there as well.”
The findings also suggest that Martian rocks may contain evidence from a time before life began, a record of sorts that Earth’s past geology has mostly erased.
“It is even possible that some Mars rocks will tell us about times when there was no life there,” he said, with organics formed instead through prebiotic chemistry or delivered from space. “We do not have an equivalent record of such a time preserved on Earth.”
The findings build on earlier research by Tice and his team that identified possible biosignatures in Mars rocks studied by NASA’s Perseverance rover.
Tice suggests, “When we looked even closer, we saw things that are easy to explain with early Martian life but very difficult to explain with only geological processes.”
The rocks contained organic carbon and key elements connected to microbial energy sources, along with chemical patterns that may show redox reactions (processes often associated with life on Earth).
“With the right collection, we could find the next step in evidence for past life on Mars or learn about the kinds of processes that eventually led to life on our planet.”
Tice and his colleagues will continue their work exploring the Martian land.
“I’m continuing to study the record of early Martian evolution as part of the PIXL instrument team on the Perseverance rover,” he said.
“In addition, I’m comparing how organisms affected some of the oldest sediments on Earth — now preserved in rocks in South Africa—with the potential biosignatures we discovered on Mars.”
Additional details about Tice and his team’s work can be found in a pair of papers, “Diverse organic molecules on Mars revealed by the first SAM TMAH experiment,” which appeared in Nature Communications, and “Redox-driven mineral and organic associations in Jezero Crater, Mars,” which was published in the journal Nature.
Chrissy Newton is a PR professional and founder of VOCAB Communications. She hosts the Rebelliously Curious podcast, which can be found on The Debrief’s YouTube Channel. Follow her on X: @ChrissyNewton and at chrissynewton.com.