Discovery that universe is expanding faster and faster earns physics Nobel

The discovery that the universe is expanding at an increasing pace with each passing moment has earned a trio of astronomers the 2011 Nobel Prize in Physics.

The 1 million Swedish krona ($1.46 million US) award will be shared among Saul Perlmutter, with the Lawrence Berkeley National Laboratory and the University of California at Berkeley; Brian Schmidt, with the Australian National University; and Adam Riess, with The Johns Hopkins University and the Space Telescope Science Institute.

The award, announced Tuesday morning in Stockholm, recognizes work that represents "the biggest shakeup in the physical sciences in the last 30 years," says Phillip Schewe, a physicist and spokesman for the Joint Quantum Institute at the University of Maryland.

"It's quite a lesson in scientific humility," he says, noting that this one discovery upended the way cosmologists viewed a universe they thought they were coming to know quite well.

Even 15 years ago, "everyone agreed that the universe was expanding," he explains. Evidence for that expansion came via observations dating to the 1920s that no matter where astronomers turned their telescopes, galaxies were receding. The more distant the galaxy, the faster the pace.

Like Magic Marker dots on an expanding balloon, galaxies were being carried along by the expansion of space-time itself.

Early on, this led to the idea that the universe began in an enormous release of energy, dubbed the Big Bang. Over the years, the idea has been refined, but the general outline has been upheld by increasingly sophisticated observations, which put the event at some 13.8 billion years ago.

As scientists filled in the picture of the universe's beginning, however, its future was still open to debate, which centered on two possible paths.

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