Nobel Prize in Physics Awarded to Two U.S. Cosmologists

Aalok Mehta
National Geographic News
October 3, 2006
U.S. scientists John C. Mather and George F. Smoot today won the 2006 Nobel Prize in Physics for their research helping to solidify the big bang theory of the origin of the universe.

Mather, of NASA's Goddard Space Flight Center in Greenbelt, Maryland, and Smoot, from the University of California, Berkeley, will each receive half of the prize, worth 10 million Swedish kronor (1.4 million U.S. dollars), for their groundbreaking studies of cosmic background radiation.

Their research provided a number of important insights into the early history of the universe and the formation of the first stars and galaxies.

"This is one of the really great discoveries in science," said Per Carlson, chair of the Nobel committee for physics. "It explains the place of mankind in the universe and explains the origins of the universe."

Studying the Background

Mather and Smoot had lead responsibilities for several of the most important experiments conducted by the COBE satellite, which was launched in November 1989 to help study the universe's cosmic microwave background radiation.

Background radiation is left over from the earliest phase of the universe. A mere 400,000 years after the universe formed in a violent explosion known as the big bang, it began to emit radiation as it cooled from an extremely hot and dense state.

Using COBE data, Mather and Smoot were able to precisely detail the nature of the microwave radiation. They verified that the radiation had a special "blackbody" spectrum, as predicted by big bang theory.

Blackbody radiation is the name given to radiation emitted by a rare type of object. The spectrum of such radiation across various wavelengths (colors) of light is dependent solely on temperature.

"The COBE results provided increased support for the big bang scenario for the origin of the Universe, as this is the only scenario that predicts the kind of cosmic microwave background radiation measured by COBE," according to a news release from the Royal Swedish Academy of Sciences, which awards the physics prize.

"It says that the radiation really did come from the big bang," Mather added in an interview with the Nobel Foundation.

"There really is not a good alternative explanation for having such a perfect blackbody spectrum. Many people looked, but no good explanation was found, and so the big bang theory is confirmed by that spectrum," he said.

(Get more information about the winners from the Nobel Foundation.)

History of the Universe

COBE also measured small directional variations in the background radiation's temperature, known as anisotropy.

These differences helped explain how and why matter began to clump into stars and galaxies instead of remaining dispersed uniformly throughout the universe.

Previous experiments had baffled scientists by providing little information to explain how galaxies could have formed.

Mather and Smoot's work paved the way for more detailed studies of the early universe.

"[The COBE] measurements also marked the inception of cosmology as a precise science," the Royal Swedish Academy wrote.

For example, NASA's Wilkinson Microwave Anisotropy Probe, a follow-up to COBE, has recently revealed much about the age, shape, and nature of the universe. (Related news: "Universe is Finite, 'Soccer Ball'-Shaped, Study Hints" [October 2003].)

Recognition for the two scientists was no surprise to Phillip Schewe, a spokesperson for the American Institute of Physics.

"They were right at the top of my list, and they have been for more than ten years," he said.

"The microwave background is the largest thing in the universe, it's the farthest out, and it's the furthest back in time," he said. "They were the first to really provide a map of this thing."

Yesterday biologists Andrew Z. Fire and Craig C. Mello were awarded the 2006 Nobel Prize in Physiology or Medicine for their discovery of RNA interference, a way cells control the expression of specific genes. The find could provide new treatments for diseases such as cancer and AIDS.

Update: October 4, 2006

On Wednesday U.S. biologist Roger D. Kornberg won the 2006 Nobel Prize in Chemistry for helping to unravel how cells make proteins using genetic information.

The Peace prize will be announced on October 13.

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