The Making of the Largest 3 D Map of the Universe

DESI, the Dark Energy Spectroscopic Instrument, will mobilize 5, 000 swiveling robots each one pointing a thin strand of fiberoptic cable to gather the light from about 35 million galaxies. The little robots are designed to fix on a series of preselected sky objects that are as distant as 12 billion lightyears away. By studying how these galaxies are drifting away from us, DESI will provide precise measurements of the accelerating rate at which the universe is expanding. This expansion rate is caused