Observations from the James Webb Space Telescope (JWST) have revealed a surprisingly low concentration of methane in the atmosphere of WASP-107 b, a bloated exoplanet orbiting a star 200 light-years away. This discovery suggests that the planet’s extreme puffiness may be due to factors other than a massive reservoir of gas or a small, rocky core. Instead, intense heat generated by the planet’s highly elliptical orbit and tidal forces from its host star may be causing its atmosphere to expand.