An article published in the journal “Proceedings of the National Academy of Sciences” reports the detection of samples rich in carbon-12, which on Earth is associated with biological processes, in Gale crater on Mars by NASA’s Mars Rover Curiosity. A team of researchers used the TLS instrument, part of Curiosity’s SAM mini-laboratory, to analyze the samples to check the amount of isotopes as well. The result is a limited presence in some samples of carbon-13 compared to that detectable in the atmosphere and in Martian meteorites. On Earth, such a result indicates that the sample was produced by some biological process. However, the researchers also offered alternative explanations related to non-biological processes.