WASP-121b is so hot that the planet has puffed up beyond its ability to hold onto its own atmosphere, and is instead streaming it away as it flies around its star every 30 hours. (Credit: NASA/ESA/J. Olmsted/STScI)

Astronomers just used NASA’s Hubble Space Telescope to take the temperature of an exoplanet called WASP-121b and discovered that the world is so hot that heavy metals actually leak behind it as it whips about its central star. It’s the first time scientists have seen such a phenom