Five-year quest to create 3D map of the universe

A five-year mission to create an unprecedented 3D map of the universe using the Dark Energy Spectroscopic Instrument (DESI), designed and built in part by UCL physicists, formally starts today. DESI will capture and study light from tens of millions of galaxies and other distant objects with the aim of unravelling the mysteries of "dark energy", which is believed to be driving the accelerating expansion of the universe. The instrument, based at Kitt Peak National Observatory near Tucson, Arizona, in the United States, contains 5,000 fibre-optic "eyes", each of which can image a galaxy in just 20 minutes. In a four-month trial run, DESI captured four million spectra - more than the combined output of all previous spectroscopic surveys. Professor Ofer Lahav, (UCL Physics & Astronomy) ,  chair of the DESI UK consortium of seven universities, said: "This survey will go deeper into space and the history of the Universe than we have ever achieved before, and follows years of efforts of building DESI by the international collaboration, including by UCL and Durham's instrumentation teams. "DESI is a revolution in astronomy, collecting spectra from 5,000 galaxies every 20 minutes. It will lead to unprecedented observations that will help us characterise the mysterious nature of dark energy." Michael Levi, the Director of DESI based at the US Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab), the project's lead institution, said: "We will measure 10 times more galaxy spectra than ever obtained.