The Eberly Telescope Dark Energy Experiment (HETDEX) has discovered tens of thousands of gigantic hydrogen gas halos, called "Lyman-alpha nebulae," surrounding galaxies 10 billion to 12 billion years ago. Known as Cosmic Noon, this is an epoch in the early universe when galaxies were growing their f astest. To spur this growth, they would have needed access to vast reservoirs of hydrogen gas, a key building block for stars. However, until recently, astronomers had only found a handful of these essential structures. ...read more read less