Clocking an Accelerating Universe: First Results from BOSS

First spectroscopic results from BOSS, the Baryon Oscillation Spectroscopic Survey, give the most detailed look yet at the time when dark energy turned on. Over six billion light years ago, halfway back to the big bang, the expanding universe slipped from the grasp of matter’s mutual gravitational attraction. Dark energy took over, and expansion began to accelerate. BOSS is the largest component of the third Sloan Digital Sky Survey, led by scientists from Berkeley Lab.