UC Berkeley, LBNL cosmologist George F. Smoot awarded 2006 Nobel Prize in Physics

03 October 2006 - BERKELEY – Cosmologist George F. Smoot, who led a team that obtained the first images of the infant universe, confirming the predictions of the Big Bang theory, was awarded the 2006 Nobel Prize in Physics today.

Smoot, a professor of physics at the University of California, Berkeley, and an astrophysicist at Lawrence Berkeley National Laboratory (LBNL), shares the prize with John C. Mather of NASA Goddard Space Flight Center in Greenbelt, Md. This is UC Berkeley’s twentieth Nobel Prize since Ernest O. Lawrence won in 1939, and its eighth physics Nobel.

Smoot, a resident of Berkeley, was surprised by an early morning call from Sweden to his unlisted cell phone, which the Nobel committee obtained by waking his neighbor.

“There were no rumors. I figured they only give the prize when you’re close to death, and I still have enough life left in me,” said Smoot, 61.

Smoot and Mather together led the building and launch of the Cosmic Background Explorer (COBE) satellite in 1989 to look for telltale signs of the primordial explosion. They announced in 1992 the discovery of residual heat from the explosion, in addition to variations in temperature across the sky that indicated the beginnings of structure in the early universe.

“Those measurements really confirmed our picture of the Big Bang,” Smoot said. “By studying the fluctuations in the microwave background, we found a tool that allowed us to explore the early universe, to see how it evolved and what it’s made of.”

The COBE results have been confirmed by subsequent balloon experiments, including the UC Berkeley-led Millimeter Anisotropy eXperiment IMaging Array (MAXIMA) experiment and its southern complement, Balloon Observations Of Millimetric Extragalactic Radiation and Geophysics (BOOMERANG), and more recently by the Wilkinson Microwave Anisotropy Probe (WMAP). Smoot, who collaborated on these experiments, is now involved with the European Space Agency’s Planck satellite, which should launch in 2008.

Smoot has been a UC Berkeley physics professor since 1994 and an astrophysicist at LBNL since 1974. He has led a succession of projects over the past 34 years that have helped to change the nature of the quest to understand the origin and evolution of the universe. Historically, cosmology had been essentially a theoretical field. Smoot was one of the first astrophysicists to devise ways to conduct experiments that produced data and information about the early universe.

“People have contemplated the origin and evolution of the universe since before the time of Aristotle,” Smoot said. “Although cosmology has been around since the time of the ancients, historically it has been dominated by theory and speculation. Very recently, the era of speculation has given way to a time of science. The advance of knowledge and of scientific ingenuity means that at long last, we can actually test our theories.”

To understand how our universe was created, Smoot has focused on clues hidden in the extremely faint heat left over from the Big Bang, which happened some 15 billion years ago. This relic radiant energy, or cosmic microwave background radiation (CMB), has been called “the message from the beginning of time.”

According to theory, all space began to expand at the moment of the Big Bang and was pervaded with the physical contents produced by the leviathan explosion, including the relic CMB radiation. To this day, CMB radiation saturates all of space throughout the universe.

In 1976, Smoot was a key member of the team that found startling evidence in the CMB that contradicted the prevailing scientific view that galaxies are spread relatively evenly throughout the universe. Instead, the data revealed that vast regions of space are virtually devoid of galaxies, while elsewhere, billions of galaxies are clustered together. These findings were met with strong skepticism, but a second set of experiments by Smoot and colleagues confirmed it: On the galactic scale, the universe has densely crowded neighborhoods and equally vast empty spaces.

The new view of the universe created by this body of work required science to rethink its theory of the origin of the universe. Cosmologists had believed that in the early universe, matter had been evenly distributed. The virtually uniform temperature of the CMB — 2.7 degrees above absolute zero — is consistent with this notion. But with the finding that the universe is “lumpy,” scientists came to believe that similarly, there should be minute variations in the CMB radiation.

Smoot began a search for these tiny fluctuations in 1974, submitting a satellite proposal to NASA to measure and map the cosmic microwave background. Fifteen years later, the COBE satellite was launched, joining a competitive quest that at that stage involved many scientific teams. In April 1992, Smoot’s team — his group involved some 40 plus people and the COBE satellite project an estimated 1,000 individuals — announced they had found what had eluded scientists for decades.

At an American Physical Society meeting in Washington, D.C., Smoot announced the discovery of colossal hot and cold regions of differing densities in the infant universe — fossil relics from the primeval explosion that began the universe. Smoot said these 15-billion-year-old fossils are the primordial seeds that grew into the galaxies and superclusters of galaxies evident today.

Said Smoot, “These small variations are the imprints of tiny ripples in the fabric of space-time put there by the primeval explosion process. They were produced at the moment of creation, when the universe we see today was so small there wasn’t enough room for a single proton. Over billions of years, gravity magnified these ripples into galaxies, clusters of galaxies, and the great voids of space.”

One newspaper in Europe published the map developed by the COBE team, labeling it a “baby photo” of the universe. Smoot says that technically, this is an accurate description. In fact, the maps show the universe as it looked when it was about one-ten-thousandth of its current age, or about 300,000 years after its birth.

Smoot was born in Yukon, Fla. His father was a hydrologist for the U.S. Geological Survey and his mother was a science teacher and school principal. Today, they live in Great Falls, Va. Smoot says his parents instilled in him a joy for learning and an interest in science and math. He received his Ph.D. in physics at the Massachusetts Institute of Technology in 1970 and decided to enter the field of cosmology, which Smoot believed was a frontier of fundamental science that was ripe for exploration.

Smoot recalls that when he started his career, cosmology wasn’t even considered a real science. “It was a fringe field,” he says. “Back then, you could get all of us in the field into a single room. I remember the teasing from my particle physics colleagues that real physics is done at accelerators. Today, opinions have changed. We have begun to explore the early universe, the original accelerator. The fields of particle physics and cosmology have been joined.”

The COBE team that Smoot headed was a large collaboration involving participants from UC Berkeley, Lawrence Berkeley National Lab, the NASA Goddard Space Flight Center, Jet Propulsion Laboratory, UCLA, MIT, and Princeton. In addition to Smoot, team members at LBNL included astrophysicist Giovanni De Amici, data analyst Jon Aymon, and Berkeley graduate students Charley Lineweaver and Luis Tenorio.

Their findings support Big Bang cosmology, a theory on the origination of the universe developed in the 1940s. The theory predicts the existence of CMB radiation, which was first detected in 1964 by Nobel Prize winners Arno Penzias and Robert Wilson. Since that time, there has been a growing awareness among scientists that the CMB is pregnant with clues to the evolution of the universe.

Says Smoot, “Human beings have had the audacity to conceive a theory of creation and now, we are able to test that theory. I believe we have discovered the fossil remnants of the progenitors of present-day structure in the universe. They tell us that we have a viable theory of the universe back to about 10-30 second. At that time the currently observable universe was smaller than the smallest dot on your TV screen, and less time had passed than it takes for light to cross that dot.”

By Robert Sanders and Jeffery Kahn, Public Affairs.

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Robert Sanders

Public Affairs

University of California, Berkeley

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