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Americans Share Nobel in Physics

A pair of researchers at Berkeley and NASA came up with the strongest evidence yet that the universe began with a big bang.

October 04, 2006|Thomas H. Maugh II | Times Staff Writer

Two astrophysicists from Berkeley and NASA won the 2006 Nobel Prize in physics on Tuesday for their discovery of the strongest evidence to date that the universe began with a big bang, a feat the Nobel committee said "marked the inception of cosmology as a precise science."

John C. Mather, 60, of NASA's Goddard Space Flight Center in Greenbelt, Md., played a major role in the design of the Cosmic Background Explorer, or COBE, satellite, launched in 1989, and was the principal investigator on one of the key experiments, which studied radiation from the infancy of the universe, 380,000 years after its creation.

George F. Smoot, 61, of UC Berkeley and the Lawrence Berkeley National Laboratory measured small temperature differences in the radiation that showed the initial distribution of matter. When their results were published in 1992, famed cosmologist Stephen Hawking called it "the greatest discovery of the century, if not of all time."

When COBE was launched, many cosmologists favored the so-called steady-state theory of the universe, which argues that matter is continually being created and destroyed throughout the cosmos.

But Smoot and Mather's results, collected in the first nine minutes of observation, provided the strongest evidence yet of the big bang. Their results so closely matched theoretical predictions that, when they presented the findings at the May 1992 meeting of the American Astronomical Society, they received a standing ovation.

"That was the first standing ovation ever at an AAS meeting," said Ed Weiler, director of the Goddard center.

Per Carlson, chairman of the Nobel physics committee, said in a teleconference that "they have not proven the big bang theory, but they give it very strong support."

According to the Nobel citation, the big bang "is the only scenario that predicts the kind of cosmic microwave background radiation measured by COBE."

The pair were not taken completely unawares by the news of the $1.37-million prize, delivered in early-morning telephone calls from Sweden.

"I can't say I am completely surprised," said Mather, the first NASA employee to win a Nobel. "People have been saying we should be awarded."

He noted that he had received so many phone calls and e-mails that he had to unplug his phone and his Blackberry crashed.

Smoot was a little more skeptical about the 2:45 a.m. call because his number is unlisted. The committee woke a neighbor to get the number.

"I wasn't sure it was them, but they sounded really serious and had Swedish accents," he said. "I wasn't really sure until I ran to my computer and pulled up the Nobel website."

Mather said the announcement was a validation of their findings. "We knew it was important. Now everybody knows it's important," he said.

Tuesday's announcement marks the second time a physics Nobel has been awarded for the observation of cosmic microwave background radiation, which is the relic of the first light to enter the universe after the big bang.

The 1978 physics prize went to Arno A. Penzias and Robert W. Wilson of the Bell Telephone Laboratories for their first observation of the radiation in the early 1960s. They showed its existence, but interference from Earth's atmosphere made precise measurements impossible.

Such measurements could be made only from space -- and COBE almost didn't make it into orbit. The final design was for a 10,000-pound satellite that would be carried aloft aboard the space shuttle, but the mission was aborted by the January 1986 explosion of the Challenger.

In despair, Smoot said Tuesday, the team began contacting European and even Russian space officials hoping to find a ride. Eventually, he added, NASA relented and offered to launch the craft aboard a Delta rocket -- but only if its weight was reduced by half.

"The other scary moment was when we went to Vandenberg [Air Force Base] for a test firing and it failed," he said. "But they said they were going to launch anyway, and fortunately it worked."

The microwave radiation emitted in the big bang has a special form, called blackbody radiation, in which the wavelength depends on its temperature. Smoot and Mather were able to show that the initial temperature of the universe was about 5,000 degrees Fahrenheit but that it slowly cooled until it reached its current value of 4.86 degrees above absolute zero.

The team was also able to measure very small changes in temperature distribution throughout the cosmos, identifying areas that were slightly cooler than the rest of the sky -- by about a hundred-thousandth of a degree. It was in these cooler areas that galaxies, stars, planets and all the other debris of the universe condensed from the primeval gas.

The conventional view when COBE was launched was that galaxies were spread uniformly throughout the universe. Smoot's findings indicated that the universe was actually "lumpy," with galaxies clustered in regions that had been the site of cool spots and vast regions of space that are virtually devoid of galaxies.

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