Fatty acids on Mars
hole drilled on Mars
Samples drilled from the dried bed of an ancient Martian lake have yielded chemical hints of past life. NASA/JPL-Caltech/MSSS
Sometimes, it takes time to appreciate what you have. Twelve years ago, NASA’s Curiosity rover, soon after landing on Mars, drilled its second rock sample ever. It discovered fossilized mud that derived from a lost lakebed more than 3 billion years old, along with some simple organic molecules, like chlorobenzene.
Now, from that same sample, the rover’s scientists have made a startling new discovery: Hidden in this clay are long-chain organic molecules, likely derived from fatty acids. On Earth, fatty acids are created by living creatures to build cell membranes. On Mars? They could be lost remnants of life—or, more likely, abiotic grit deposited long ago by meteorites.
Either way, the finding—which required years of painstaking reanalysis and experimentation, on Mars and Earth—is another tantalizing result from a mission that has long specialized in them. It bolsters the odds that the samples being collected by the Perseverance rover for ferrying to Earth could contain similar compounds, which could easily be divined in labs on this planet.
But Curiosity’s scientists haven’t given up hope that the rover could make such a finding first. They have one pristine sample left from that second drill hole—and one last shot at detecting the fingerprints of life in it.
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