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Curiosity has maintained pristine pieces of the Cumberland sample in a “doggy bag” so that the team could have the rover revisit it later, even miles away from the site where it was collected. The team developed and tested innovative methods in its lab on Earth before sending messages to the rover to try experiments on the sample.
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In a quest to see whether amino acids, the building blocks of proteins, existed in the sample, the team instructed the rover to heat up the sample twice within SAM’s oven. When it measured the mass of the molecules released during heating, there weren’t any amino acids, but they found something entirely unexpected.
An intriguing detection
The team was surprised to detect small amounts of decane, undecane and dodecane, so it had to conduct a reverse experiment on Earth to determine whether these organic compounds were the remnants of the fatty acids undecanoic acid, dodecanoic acid and tridecanoic acid, respectively.
The scientists mixed undecanoic acid into a clay similar to what exists on Mars and heated it up in a way that mimicked conditions within SAM’s oven. The undecanoic acid released decane, just like what Curiosity detected.
Each fatty acid remnant detected by Curiosity was made with a long chain of 11 to 13 carbon atoms. Previous molecules detected on Mars were smaller, meaning their atomic weight was less than the molecules found in the new study, and simpler.
“It’s notable that non-biological processes typically make shorter fatty acids, with less than 12 carbons,” said study coauthor Dr. Amy Williams, associate professor of geology at the University of Florida and assistant director of the Astraeus Space Institute, in an email. “Larger and more complex molecules are likely what are required for an origin of life, if it ever occurred on Mars.” |
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