Type Ia supernovae are bright “standard candles” for measuring cosmic distances. Standard enough to discover dark energy, they’re far from identical. Researchers at the Berkeley Lab-based Nearby Supernova Factory have shown that supernova twins with closely matching spectra double the accuracy of distance measures.
The U.S. Department of Energy has announced approval of Critical Decision 2 (CD–2), authorizing the scientific scope, schedule, and funding profile of DESI, the Dark Energy Spectroscopic Instrument, an exceptional apparatus designed to improve our understanding of the role of dark energy in the expansion history of the universe.
The Baryon Oscillation Spectroscopic Survey (BOSS) pioneered the use of quasars to chart the universe’s expansion and investigate the properties of dark energy through studies of large-scale structure. New techniques of analysis led by Berkeley Lab scientists, combined with other new BOSS quasar measures of the young universe’s structure, have produced the most precise measurement of expansion since galaxies formed.
In 1996 Uros Seljak was a postdoc at Harvard, contemplating ways to extract information from the cosmic microwave background (CMB). The distribution of anisotropies, slight temperature differences, in the CMB had much to say about the large-scale structure of the universe. If it were also possible to detect the polarization of the CMB itself, however,
The Baryon Oscillation Spectroscopic Survey (BOSS), the largest component of the third Sloan Digital Sky Survey, has measured the clustering of nearly 1.3 million galaxies spectroscopically to determine the “standard ruler” of the universe’s large-scale structure to within one percent. This is the most precise such measurement ever made and is likely to establish the standard for years to come.
New results from IceCube, the neutrino observatory buried at the South Pole, may show the way to locating and identifying cosmic accelerators in our galaxy that are 40 million times more powerful than the Large Hadron Collider at CERN.