In only seven months, the Dark Energy Spectroscopic Instrument (DESI) has catalogued approximately 8 million galaxies, creating the largest 3D map of the universe yet. And it will get even bigger as DESI continues its five-year mission to survey the cosmos. The specially designed instrument is installed on the Nicholas U. Mayall 4-meter telescope at Kitt Peak National Observatory in Arizona, and measures the shift in wavelengths of light emitted by distant galaxies. "When we make this 3D map, what we are really doing is measuring the universe's expansion history," said Julien Guy of the Lawrence Berkeley National Laboratory.