NASA’s James Webb Space Telescope observed the exoplanet WASP-80 b as it passed in front of and behind its host star, revealing spectra indicative of an atmosphere containing methane gas and water vapor. While water vapor has been detected in over a dozen planets to date, until recently methane – a molecule found in abundance in the atmospheres of Jupiter, Saturn, Uranus, and Neptune within our solar system – has remained elusive in the atmospheres of transiting exoplanets when studied with space-based spectroscopy. Taylor Bell from the Bay Area Environmental Research Institute (BAERI), working at NASA’s Ames Research Center in California’s Silicon Valley, and Luis Welbanks from Arizona State University tell us more about the significance of discovering methane in exoplanet atmospheres and discuss how Webb observations facilitated the identification of this long-sought-after molecule. These findings were recently published in the scientific journal Nature. Vivien Parmentier, researcher at Côte d'Azur Observatory, participated in the analysis and interpretation of the data. Now that this first overview of the data has been published, he and phd Nishil Mehta at Côte d'Azur Observatory will study the interaction between chemistry and atmospheric circulation using complex three-dimensional models.