3 US-born men win physics Nobel

Associated Press

NEW YORK

Three U.S.-born scientists won the Nobel Prize in physics Tuesday for discovering that the universe is expanding at an accelerating pace, a stunning revelation that suggests the cosmos could be headed for a colder, bleaker future, nearly devoid of light.

In 1998, Saul Perlmutter, Brian Schmidt and Adam Riess presented findings that overturned the conventional idea that the expansion was slowing 13.7 billion years after the big bang.

Their discovery raised a question: What is pushing the universe apart? Scientists have labeled it “dark energy,” but nobody knows what it is.

It’s “an enigma, perhaps the greatest in physics today,” the Nobel committee said.

Perlmutter, 52, of the Lawrence Berkeley National Laboratory and University of California, Berkeley, will receive half the $1.5 million prize. The other half will go to Schmidt, 44, at the Australian National University in Weston Creek, Australia, and Riess, 41, an astronomy professor at Johns Hopkins University and Space Telescope Science Institute in Baltimore.

Working in two teams, with Perlmutter heading one, they had raced to measure the universe’s expansion by analyzing light from dozens of exploding stars called supernovas. They found the light was weaker than expected, signaling that the expansion of the universe was accelerating.

It was “one of the truly great discoveries in the history of science, and one whose implications are not fully understood,” said Paul Steinhardt, a physics professor at Princeton University.