Curiosity Discovers Largest Carbon Molecules on Mars – Could Be Traces of Ancient Life

The largest carbon molecules have been discovered on Mars for the first time. With a high degree of probability, these may be traces of ancient life on the planet. In a laboratory on Earth, scientists reproduced similar chemical processes, simulating conditions on Mars, and obtained a similar result. The repeatability of the experiment indicates the correctness of the guess – billions of years ago, Mars could have been home to biological life.

Image source: NASA

The discovery was made by NASA’s Curiosity rover, which drilled into Gale Crater, which is thought to be the bottom of an ancient lake. If so, the site should contain organic deposits, making it an excellent site for searching for traces of ancient life.

Sample collection location

The rover extracted a sample from a shallow borehole and placed it in its mass spectrometer. The experiment required that molecular oxygen be removed from the sample first, which was successfully accomplished. In particular, the temperature in the chamber was raised to 850 °C before the main measurements.

Among the data obtained, several of the longest carbon chains were found in extremely low concentrations: decane (C₁₀H₂₂), undecane (C₁₁H₂₄) and dodecane (C₁₂H₂₆). These are linear molecules, the stability of which is significantly lower than that of ring molecules. Curiosity had previously detected ring (aromatic) carbon molecules in samples from Mars. Long molecules of alkanes – saturated hydrocarbons – were detected for the first time. The rover confirmed that it can detect them, and this in itself is an incredibly valuable experience.

The presence of such molecules on Mars could be an important clue to geological or perhaps even biological processes that occurred there in the past, since such long chains are usually associated with the decomposition of organic material. If of inorganic origin, they could also arise in hydrothermal systems.

«The fact that fragile linear molecules are still present on the surface of Mars 3.7 billion years after they formed allows us to make a new claim: if life ever arose on Mars billions of years ago, at the same time as life arose on Earth, chemical signatures of that ancient life may still be present today, and we can detect them,” the scientists explained in an interview with ScienceAlert.