by Lynn Yarris
Lawrence Berkeley National Laboratory
George F. Smoot, 61, leader of a research team that was able to image the infant universe, revealing a pattern of miniscule temperature variations that evolved into the universe we see today, has been awarded the 2006 Nobel Prize in physics. He shares the award with John C. Mather of NASA Goddard Space Flight Center. The citation reads "for their discovery of the blackbody form and anisotropy of the cosmic microwave background radiation."
Smoot has been an astrophysicist at Lawrence Berkeley National Laboratory (LBNL) since 1974 and a University of California at Berkeley physics professor since 1994. He is LBNL's 11th Nobel laureate.
"A member of the Nobel Committee called me at around 2:45 am. He had a Swedish accent, and told me that John Mather and I were sharing the Nobel Prize in physics," said Smoot. "I soon talked to someone I knew personally and, by the time the phone call had ended, I was convinced it was legitimate. The ceremony is December 10, which is when I have scheduled a final exam for my students, so I will have to do some rescheduling. The upside, though, is that maybe now my students will pay more attention to me."
On May 1, 1992, at a meeting of the American Physical Society (APS), Smoot made an announcement that essentially silenced all the scientific critics of the Big Bang theory and helped change the course of future investigations into the origin and evolution of the universe. Smoot and his research team, after analyzing hundreds of millions of precision measurements in the data they'd gathered from an experiment aboard NASA's Cosmic Background Explorer (COBE) satellite,
had produced maps of the entire sky, which showed "hot" and "cold" regions with temperature differences of a hundred-thousandth of a degree. These temperature fluctuations, produced when
the universe was smaller than a single proton, were consistent with Big Bang predictions and are believed to be the primordial seeds from which our present universe grew.
"At the time captured in our images, the currently observable universe was smaller than the smallest dot on your TV screen," Smoot said, "and less time had passed than it takes for light to cross that dot."
Theorists had been predicting temperature variations in the ancient universe since the Big Bang theory was first developed in the 1940s. However, until Smoot and his team announced their discovery, the cosmic background radiation, microwaves left over from the Big Bang that have taken some 15 billion years to reach Earth, had appeared to be persistently uniform.
Without temperature variations there would be no ripples in the fabric of space that gravity, working over the great expanse of time, could magnify into the universe we observe today.
Since Smoot's announcement in 1992, subsequent cosmic microwave background experiments, including data from the MAXIMA and BOOMERANG balloon flights and the WMAP satellite, have confirmed and refined the original maps. With the results of his team's discovery, based on measurements made using differential microwave radiometers (DMRs) that they designed and built, Smoot provided the strongest evidence yet that the Big Bang theory is correct.
As Smoot explained, "The tiny temperature variations we discovered are the imprints of tiny ripples in the fabric of space-time put there by the primeval explosion process. Over billions of years, the smaller of these ripples have grown into galaxies, clusters of galaxies, and the great voids in space."
Smoot was one of the first astrophysicists to devise ways of conducting experiments that produce data and information about the early universe.
"People have contemplated the origin and evolution of the universe since before the time of Aristotle," he 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 focused on clues hidden in the extremely faint heat left over from the Big Bang. This relic radiant energy, or cosmic microwave background radiation (CMB), has been called a "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.
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 uniformly 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.
The new view of the universe created by this discovery required scientists to rethink the origin of the universe.
At the May 1, 1992, APS meeting in Washington, D.C., Smoot made his historic announcement of the discovery of the hot and cold regions of differing densities in the infant universe. A map developed by the COBE team was called a "baby photo" of the universe. The map showed the universe as it looked when it was about one-ten-thousandth of its current age, or about 300,000 years after its birth.
