A large international team of researchers used Curiosity’s Sample Analysis at Mars (SAM) suite of instruments to measure the abundances of different gases and isotopes in samples of Martian air. This is an artist’s impression of habitable Mars (Daein Ballard / CC BY-SA 3.0) Isotopes are variations of the same chemical element that contain different numbers of neutrons, such as the most common carbon isotope, carbon-12, and a heavier stable...
