Two Lonely Gas Blobs

Astronomers have found two ancient clouds of gas in interstellar space that contain no elements heavier than deuterium (Science, DOI: 10.1126/science.1213581). Until now all gas clouds detected have contained elements heavier than helium, indicating that they’d once been part of the makeup of a star, where primordial light elements fused together to make heavier elements. These two newly discovered clouds, the light from which comes from 2 billion years after the Big Bang, have therefore never been involved in star production. Michele Fumagalli of the University of California, Santa Cruz, and colleagues detected the clouds with spectrometers on the Keck I Telescope atop Mauna Kea in Hawaii. “It’s quite exciting, because it’s the first evidence that fully matches the composition of the primordial gas predicted by the Big Bang theory,” Fumagalli says.