The verdict is in — mostly. The bright spots on the dwarf planet Ceres are probably made of salt, NASA’s Dawn spacecraft has found.
Mixed with the salt are bits of rock and frozen water. When sunlight hits the blend, the ice sublimates into a misty haze above two of Ceres’s craters, researchers report in the 10 December issue of Nature.
But mission scientists are not sure how the salt, ice and haze are interlinked. “The whole picture we do not have yet,” says Andreas Nathues, a planetary scientist at the Max Planck Institute for Solar System Research in Goettingen, Germany, and the paper’s lead author1.