Saul Perlmutter of Berkeley Lab and UC Berkeley has won the 2011 Nobel Prize in physics for his work with the Supernova Cosmology Project. He is the 57th University of California researcher to be honored with a Nobel Prize.

Perlmutter shares the prize with High-z Supernova Search Team members Brian Schmidt of Australian National University in Weston Creek, Australia, and Adam Riess of Johns Hopkins University and Space Telescope Science Institute in Baltimore. At the time of the 1998 discovery, Reiss was a postdoctoral fellow at UC Berkeley working with astronomer Alex Filippenko, who at different times was a member of both teams.

The winners' respective teams had raced to map the universe by locating the most distant supernovae. Each team found more than 50 supernovae whose light was weaker than expected — an indication that the expansion of the universe was accelerating. "If the expansion will continue to speed up the universe will end in ice," reads the Nobel press release.

On learning of the award, Perlmutter said, "I am delighted, excited and deeply honored. It's wonderful that the Nobel Prize is being awarded for results which reflect humanity's long quest to understand our world and how we got here. The ideas and discoveries that led to our ability to measure the expansion history of the universe have a truly international heritage, with key contributions from almost every continent and culture. And quite appropriately, our result — the acceleration of the universe — was the product of two teams of scientists from around the world. These are the kinds of discoveries that the whole world can feel a part of and celebrate, as humanity advances its knowledge of our universe."

Berkeley Lab's Director Paul Alivisatos said, "I extend my warmest congratulations to Saul Perlmutter, Brian Schmidt and Adam Riess for their receipt of the Nobel Prize in physics, honoring the independent discovery by their two teams of the accelerating expansion of the universe, propelled by dark energy. By revealing that what we can see and understand in the sky represents only a few percent of a much larger reality — a cosmos filled with mystery and demanding exploration — these researchers and their colleagues have opened a new path leading toward fundamental discoveries about the origin and fate of the universe. I'm particularly proud that some of the earliest steps on this path were taken here at Berkeley Lab with the founding of the Supernova Cosmology Project in the late 1980s."

The accelerating expansion of the universe was discovered after years of work by the Supernova Cosmology Project, an international collaboration of researchers from the United States, France, Sweden, the United Kingdom, Chile, Japan, Spain and other countries, based at Berkeley Lab. The Supernova Cosmology Project was cofounded by Perlmutter in 1988 to devise methods of using distant supernovae to measure the expansion rate of the universe.

Another group of astronomers and physicists began a similar search in the mid-1990s, reaching the same conclusion at nearly the same time as the Supernova Cosmology Project. The independent findings of the Supernova Cosmology Project and the High-Z Supernova Search Team, led by Schmidt and of which Riess was a prominent member, were jointly named the "breakthrough of the year" by the journal Science in 1998.

The accelerating expansion of the universe implies the existence of so-called dark energy, a mysterious force that acts to oppose gravity and increase the distance among galaxies. The nature of dark energy is unknown and has been termed the most important problem facing 21st century physics.

“This discovery was very much a team effort,” Perlmutter stressed, citing the efforts of the Supernova Cosmology Project’s individual members in theoretical studies of supernova dynamics, the detection of supernovae near and far, data analysis and interpretation, and other research components.

In recent years, Perlmutter has been working with NASA and the U.S. Department of Energy (DOE) to build and launch the first space-based observatory designed specifically to understand the nature of dark energy. A dark-energy mission was named the top telescope-building priority in an August 2010 report from a blue-ribbon committee of the National Academy of Sciences.

Perlmutter graduated magna cum laude in physics from Harvard University in 1981 and began graduate work at the UC Berkeley, where he gravitated toward the study of astrophysics. He completed his Ph.D. with Richard Muller, UC Berkeley professor of physics, in 1986.

A member of the National Academy of Sciences and a fellow of the American Academy of Arts and Sciences, Perlmutter has received numerous honors, including the 2006 Shaw Prize, shared with Schmidt and Riess; the 2007 Gruber Cosmology Prize, which he shared with his entire Supernova Cosmology Project team and the High-Z Supernova Search team; the 2003 California Scientist of the Year award; and the 2002 E. O. Lawrence Award in physics from the Department of Energy.

He lives in Berkeley with his wife and daughter.

UC Berkeley and Berkeley Lab contributed to this report.