The 2011 Nobel Prize in physics was awarded today to Saul Perlmutter at the Lawrence Berkeley National Lab, Brian Schmidt at the Australian National Lab and Adam Reiss at Johns Hopkins University for their discovery of the accelerating expansion of the universe.

“In a universe which is dominated by matter, one would expect gravity eventually should make the expansion slow down, the Royal Swedish Academy’s Olga Botner said this morning at the announcement event in Stockholm. "Imagine then the utter astonishment when two groups of scientists headed by this year’s Nobel Laureates in 1998 discovered that the expansion was not slowing down, it was actually accelerating."

"By comparing the brightness of distant, far-away supernovae with the brightness of nearby supernovae," Botner continued, "the scientists discovered that the far-away supernovae were about 25 percent too faint. They were too far away. The universe was accelerating. And so this discovery is fundamental and a milestone for cosmology. And a challenge for generations of scientists to come.”

For a 2004 article in Scientific American by Riess about the use of distant supernovae to reveal the acceleration of the universe, click here.

And click here for a profile of Perlmutter and his work on dark energy.