KPNO/NOIRLab/NSF/AURA/P. Marenfeld Astrophysicists at the Center for Astrophysics | Harvard & Smithsonian (CfA) released a cosmic map using 2,400 galaxies in 1983. Now, CfA scientists are aiming to map 30 million. In the largest quest yet to map the universe, an international team of researchers is using DESI, or the Dark Energy Spectroscopic Instrument, to survey the skies. Observations officially began today, May 17, at Kitt Peak National Observatory near Tucson, Arizona; the mission will last five years with the goal of mapping 30 million galaxies. By surveying a vast volume of space, the scientists of the DESI collaboration, including a dozen from the CfA, will be able to address a myriad of questions in modern cosmology: how does the early universe create large-scale structures, how does gravity cause matter to collect and form galaxies, and what might be driving the enigmatic acceleration of the expansion of the universe?