Mars rover exploring on the planet surface. iStock Photos
In a breakthrough discovery, researchers have found the largest organic compounds ever seen on Mars, offering new clues about whether life once existed on the Red Planet.
Buried within a 3.7-billion-year-old rock sample, the largest organic compounds ever found on Mars have been uncovered by NASA’s Curiosity rover—a six-wheeled lone explorer traversing the planet.
The discovery was made in Yellowknife Bay, a former lakebed that once held all the right conditions for life to emerge.
Tests conducted onboard the rover suggest that the rock contains long-chain alkanes—organic molecules believed to be remnants of fatty acids.
While these compounds can form through non-biological chemical reactions, they are also essential building blocks of cell membranes in all living organisms on Earth.
The researchers, however, have not reported finding a biosignature—defined as any ‘characteristic, element, molecule, substance, or feature’ that serves as evidence of past or present life.
Still, one expert noted that this material represents the best chance yet for identifying signs of ancient life on Mars.
“These molecules can be made by chemistry or biology,” Dr Caroline Freissinet, an analytical chemist, said.
“If we have long-chain fatty acids on Mars, those could come – and it’s only one hypothesis – from membrane degradation of cells present 3.7bn years ago.”
Largest Organic compounds found
In the fresh study, Freissinet and her colleagues developed a new procedure to analyze a larger portion of the mudstone sample.
As a result, Curiosity detected significantly larger organic molecules, including decane, undecane, and dodecane.
During their research, scientists analyzed a sample named Cumberland, which likely contained carboxylic acids, or fatty acids, that transformed into alkanes during the heating process
“Although abiotic processes can form these acids, they are considered universal products of biochemistry, terrestrial, and perhaps Martian,” the scientists said.
On deeper analysis, the scientists discovered that Martian organics made fatty acids by adding two carbon atoms at a time, just like organisms on Earth.
“The one in the middle with 12 carbons is more abundant than the other two.
We have the same trend on Mars, but a trend drawn from three molecules is not a real trend. Still, it’s very intriguing,” Freissinet said.
Clues to life
The recent finding bolsters hopes that organic signatures of life can persist in Martian rock for billions of years, raising the chances of detecting past life.
The Martian explorer is carrying another rock sample that may reveal larger organics, potentially reinforcing evidence of even-numbered fatty acids.
Curiosity’s journey began in 2011, embarking on a mission to explore Mars’ past.
Over the years, it has traveled more than 20 miles (32 km) across Gale Crater, uncovering clues about the planet’s ancient environment.
Six years into the mission, NASA’s explorer detected organics in ancient mudstone, though only short carbon-chain molecules. Since October 2023, it has been exploring a sulfate-rich region of Mars.
For over seven years, Curiosity has also been climbing Mount Sharp, analyzing its layered formations.
The study has been published in the journal Proceedings of the National Academy of Sciences.
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Neetika Walter With over a decade-long career in journalism, Neetika Walter has worked with The Economic Times, ANI, and Hindustan Times, covering politics, business, technology, and the clean energy sector. Passionate about contemporary culture, books, poetry, and storytelling, she brings depth and insight to her writing. When she isn’t chasing stories, she’s likely lost in a book or enjoying the company of her dogs.
