Researchers studying crushed rock on NASA’s Curiosity rover have discovered the biggest organic molecules ever found on Mars. Organic molecules contain carbon and are key to life’s chemistry. The journal Proceedings of the National Academy of Sciences published this news. This discovery shows that Mars might have had more advanced chemistry long ago than scientists thought.

The scientists used Curiosity’s onboard lab, called Sample Analysis at Mars, or SAM, to study a rock sample. They found three molecules: decane, undecane, and dodecane. Decane has 10 carbon atoms, undecane has 11, and dodecane has 12. These molecules could be pieces of fatty acids, which are organic compounds. On Earth, fatty acids help build cell walls and support life’s functions. However, geological processes, like water mixing with minerals in hot vents, can also create fatty acids without life.

Scientists cannot yet say if these molecules came from living things or natural processes. Even so, finding them excites researchers. Earlier, Curiosity found smaller, simpler organic molecules on Mars. These larger ones suggest chemistry on Mars grew complex enough to possibly support life’s beginnings.

Why This Matters

The rover drilled the sample, named “Cumberland,” from Gale Crater in 2013. Curiosity has explored this crater since 2012. The sample revealed decane, undecane, and dodecane when heated in SAM’s oven. These are the largest organic molecules found on Mars so far. This finding raises hope that biosignatures – molecules made only by life – might still exist on Mars. Radiation and oxidation usually destroy such compounds over millions of years, but this discovery suggests some survive.

Bringing Mars samples to Earth could help scientists study them with better tools. Lead researcher Caroline Freissinet believes analyzing these samples could reveal if life once existed on Mars. She works at the French National Centre for Scientific Research (CNRS). Freissinet also helped identify organic molecules in the Cumberland sample back in 2015.

Bringing Mars samples to Earth will be one of the goals of ESA’s upcoming ExoMars mission launched in 2028, and of the joint NASA-ESA Mars Sample Return mission in the 2030s, notes a CNRS press release.

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