A peculiar chemical compound has been found to be ubiquitous in interstellar gas clouds throughout our Milky Way galaxy and may give scientists a better way to track hydrogen across the universe. The compound, called hydrogen fluoride, was detected by the European-built Herschel infrared space observatory. It is a mix of the elements hydrogen and fluorine and could serve as a signpost for astronomers trying to track hydrogen caches in the cosmos, researchers said. Read more