Baryon acoustic oscillations provides a “standard ruler” for the Universe, a way to measure the details of dark energy.

Gravitational lensing, which depends on Einstein’s Theory of General Relativity, directly tests its ability to predict the growth of large-scale structure.

BOSS, the Baryon Oscillation Spectroscopic Survey, is the most ambitious attempt yet to map the expansion history of the Universe using the technique known as baryon acoustic oscillation. BOSS achieved first light on September 14 with an upgraded spectrographic system on the 2.5-meter telescope at Apache Point Observatory.

The Nearby Supernova Factory has discovered an efficient method for standardizing the intrinsic brightness and thus the distance to the cosmic milestones known as Type Ia supernovae. The discovery underlines the crucial importance of spectroscopy in the quest to understand dark energy.