Astronomers have unveiled one of the most ambitious maps yet of the early universe, revealing a vast "sea of light" between galaxies that had remained otherwise hidden in previous surveys.
Using data from the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX), researchers created a 3D map of light emitted by excited hydrogen 9 to 11 billion years ago, when the universe was in the throes of "cosmic noon," its peak era of star formation. This specific form of light, known as Lyman-alpha, is produced when hydrogen atoms are energized by radiation from young, hot stars, creating a distinctive ultraviolet glow that can be traced across vast cosmic distances.
