Previous studies of 55 Cancri e using data from NASA’s now-retired Spitzer Space Telescope suggested the presence of a substantial atmosphere rich in volatiles (molecules that occur in gas form on Earth) like oxygen, nitrogen, and carbon dioxide. But researchers could not rule out another possibility: that the planet is bare, save for a tenuous shroud of vaporized rock, rich in elements like silicon, iron, aluminum, and calcium. “The planet is so hot that some of the molten rock should evaporate,” explained Hu.