ALMA Scientists Uncover the Mystery of Early Massive Galaxies Running on Empty

Early massive galaxies—those that formed in the three billion years following the Big Bang—should have contained large amounts of cold hydrogen gas, the fuel required to make stars. But scientists observing the early Universe with the Atacama Large Millimeter/submillimeter Array (ALMA) and the Hubble Space Telescope have spotted something strange: half a dozen early massive galaxies that ran out of fuel.