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WASHINGTON, D.C. – Secretary of Energy Steven Chu today congratulated Saul Perlmutter, a physicist at DOE’s Lawrence Berkeley National Laboratory (LBNL) and a professor of physics at the University of California at Berkeley, for winning the 2011 Nobel Prize in Physics “for the discovery of the accelerating expansion of the Universe through observations of distant supernovae.”  

“I offer my congratulations to Dr. Perlmutter and the entire Berkeley Lab team for their extraordinary contributions to science, which are being recognized with the 2011 Nobel Prize in Physics,” said Secretary Chu, who was a 1997 Nobel Prize winner in Physics and former director at LBNL. “His groundbreaking work showed us that the expansion of the universe is actually speeding up, rather than slowing down. Dr. Perlmutter's award is another reminder of the incredible talent and world leading expertise America has at our National Laboratories. On a more personal note, I am delighted about this well-deserved recognition and to have worked with Saul during the time I spent at the Berkeley Lab."

Perlmutter shares the prize with Brian Schmidt of the Australian National University and Adam Riess of Johns Hopkins University and Space Telescope Science Institute.

The discovery that the expansion of the universe is accelerating came after ten years of work by the Supernova Cosmology Project, an international collaboration of physicists and astronomers led by Perlmutter.  The group measured the expansion rate of the universe by observing distant supernovae.  Schmidt was the leader and Riess was a key member of another group of scientists called the High-Z Supernova Search Team, which began a similar study in the 1990s.  The two independent groups reached identical conclusions at nearly the same time, and their joint discovery was named "breakthrough of the year" for 1998 by the journal Science. 

It has been known since 1929 that the universe was expanding, but the expansion was assumed to be slowing due to the pull of gravity.  The fact that it is speeding up instead means there must be a source of “antigravity” in the universe.  The nature of this so-called “dark energy” is unknown.

DOE’s Office of Science has supported Perlmutter’s research efforts at LBNL since 1983 and currently supports supernova surveys and several additional projects studying dark energy. The early work on supernovae was supported by LBNL though Laboratory Directed Research and Development funds, as was the work of George Smoot who was awarded the Nobel Prize in 2006 for his work on cosmology. The Office of High Energy Physics within the Office of Science is also to be commended for their farsighted wisdom in allowing cosmology to become part of their program in the 1980s, when both of these programs began.

The Department’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time.  For more information, please visit

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