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BOSS Quasars Unveil a New Era in the Expansion History of the Universe

By collecting tens of thousands of quasar spectra, the Baryon Oscillation Spectroscopic Survey (BOSS) has measured the large-scale structure of the early universe for the first time. Like backlights in the fog, the quasars illuminate clouds of hydrogen gas along the line of sight. No other technique can reach back over 10 billion years to probe structure at a time when the expansion of the universe was still decelerating and dark energy was yet to turn on.

Closest Type Ia Supernova in Decades Solves a Cosmic Mystery

Even as the “supernova of a generation” came into view in backyards across the northern hemisphere last August, physicists and astronomers who had caught its earliest moments were developing a surprising and much clearer picture of what happens during a titanic Type Ia explosion. Now they have announced the closest, most detailed look ever at one of the universe’s brightest “standard candles,” the celestial mileposts that led to the discovery of dark energy.

Berkeley Lab's Saul Perlmutter wins Nobel Prize in Physics

Saul Perlmutter of Lawrence Berkeley National Laboratory’s Physics Division and the University of California at Berkeley has won the 2011 Nobel Prize in Physics for the discovery of the accelerating expansion of the universe through observations of distant supernovae. Perlmutter, a founder of the Supernova Cosmology Project at Berkeley Lab, shares the prize with Brian Schmidt and Adam Riess, members of the High-z Supernova Search Team who made the same discovery.

Measuring the Distant Universe in 3-D

The biggest 3-D map of the distant universe ever made, showing the distribution of intergalactic clouds of gas by using light from 14,000 galaxy-eating black holes over 10 billion light years away, has been announced by the Baryon Oscillation Spectroscopic Survey (BOSS), the largest survey in the third Sloan Digital Sky Survey. The result proves that the technique, never attempted before, can be used to study dark energy in the early universe.

The Saga of the Dark Universe Finds a Spell-binding Bard

Excerpts from a review of Richard Panek’s “The 4 Percent Universe: Dark Matter, Dark Energy, and the Race to Discover the Rest of Reality,” published by Houghton Mifflin Harcourt on January 10: in relating the discovery of dark matter and dark energy, the author shows how physicists and astronomers at Berkeley Lab and UC Berkeley not only contributed to the study of dark matter but pioneered the techniques that revealed the existence of dark energy. Berkeley Lab scientists remain at the forefront of research into the nature of the dark universe.

Astronomers Release the Largest Color Image of the Sky Ever Made

The largest image of the sky yet made – more than a trillion pixels – has been released by the multi-institutional third Sloan Digital Sky Survey (SDSS-III) at a press conference at the American Astronomical Society meeting in Seattle. The largest component of SDSS-III is the Baryon Oscillation Spectroscopic Survey, BOSS, led by Berkeley Lab scientists, now engaged in producing an even larger map of the sky.

Searching for Dark Energy with the Whole World’s Supernova Dataset

The Supernova Cosmology Project’s Union2 compilation and reanalysis of decades of the world’s best supernova surveys, with the addition of six high-redshift supernovae, puts new bounds on possible values for the nature of dark energy. Einstein’s cosmological constant comfortably fits the data, but there’s still plenty of room at the top for dynamical theories.

Measuring a Monstrous Supernova

Members of the Nearby Supernova Factory based at Berkeley Lab discovered and analyzed a rare Type Ia supernova whose progenitor star had a mass some two and a half times that of our sun – much more mass than a Type Ia progenitor should be able to accumulate before it explodes. The data they gathered is the most complete ever for such an unusual beast; only one model really fits, the merger of two white dwarf stars.

Foiling an Attack on General Relativity

In an attempt to explain away invisible dark matter and dark energy, some theorists have offered new theories of gravity that try to improve on Einstein’s General Theory of Relativity. A new study inspired by the work of a Berkeley Lab cosmologist indicates that at least one of these new theories is wrong.

Weak Lensing Gains Strength

Berkeley Lab cosmologists were part of an international team that has extended the relationship between the x-ray luminosity and the mass of galaxy clusters as measured by gravitational lensing, improving the reliability of mass measurements of much older, more distant, and smaller galactic structures. These refined measurements will benefit both the understanding of dark matter and the nature of dark energy as well.