Wednesday, October 5, 2011

Nobel Prize for 3 who know how world ends

Three US-born scientists won the Nobel Prize in physics yesterday for overturning a fundamental assumption in their field by showing that the expansion of the universe is constantly accelerating.

Their discovery created a new portrait of the eventual fate of the universe: a place of super-low temperatures and black skies unbroken by the light of galaxies moving away from each other at incredible speed.

Physicists had assumed for decades that the expansion of the universe was getting ever-slower, meaning that in billions of years it would resemble today's universe in many important ways.

Then, working in separate research teams during the 1990s, Saul Perlmutter, Brian Schmidt and Adam Riess found that the light from more than 50 distant exploding stars was far weaker than they expected, meaning that galaxies had to be racing away from each other at increasing speed.

The acceleration is driven by what scientists call dark energy, a cosmic force that is one of the great mysteries of the universe.


The Nobel-winning discovery implies instead that the universe will get increasingly colder as matter spreads across ever-vaster distances in space, said Lars Bergstrom, secretary of the Nobel physics committee.

He said galaxies that are 3 million light years away from Earth move at a speed of around 70 kilometers per second. Galaxies 6 million light years away move twice as fast.

The research implies that billions of years from now, the universe will become "a very, very large, but very cold and lonely place," said Charles Blue, spokesman for the American Institute of Physics. In contrast to the big bang, that fate has been called the "big rip" to indicate how galaxies would be torn apart, he said.

Galaxies will be flying away so quickly that their light could not travel across the universe to distant observers as it does today, making the sky appear black, he said.

"For almost a century the universe has been known to be expanding as a consequence of the Big Bang about 14 billion years ago," the citation said. "However, the discovery that this expansion is accelerating is astounding. If the expansion will continue to speed up the universe will end in ice."

The Royal Swedish Academy of Sciences said Perlmutter would receive half the 10 million kronor (US$1.5 million) award, with Riess and Schmidt, a US-born Australian, splitting the other half.

Perlmutter, 52, heads the Supernova Cosmology Project at the Lawrence Berkeley National Laboratory and University of California, Berkeley.

Suspicious

Schmidt, 44, is head of the High-z Supernova Search Team at the Australian National University in Weston Creek, Australia.

Riess, 41, is an astronomy professor at Johns Hopkins University and Space Telescope Science Institute in Baltimore, Maryland.

Schmidt said he was sitting down to dinner with his family in Canberra when the phone call came.

"I was somewhat suspicious when the Swedish voice came on," Schmidt said. "My knees sort of went weak and I had to walk around and sort my senses out."

Riess said his "jaw dropped" when he received a call at his home in Baltimore from a bunch of Swedish men and realized "it wasn't Ikea."

Perlmutter said his team made the discovery in steps, analyzing the data and assuming it wrong. "After months, you finally believe it," he said. "It's not quite a surprise anymore. I tell people it's the longest 'aha!' experience you've ever had."

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