Astronomers using the Multi Unit Spectroscopic Explorer (MUSE) instrument on ESO’s Very Large Telescope have discovered an unexpected abundance of Lyman-alpha emission in the Hubble Ultra Deep Field, a galaxy-rich patch of the southern constellation Fornax. The discovered emission covers nearly the entire field of view, leading the scientists to extrapolate that nearly all the sky in the early Universe is invisibly glowing with Lyman-alpha emission. The...
