- Press Release
- Oct 31, 2023
George Smoot Wins Nobel Prize in Physics
BERKELEY, CA – George F. Smoot, 61, leader of a research team that was able to image the infant universe, revealing a pattern of miniscule temperature variations which evolved into the universe we see today, has been awarded the 2006 Nobel Prize for 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 (Berkeley Lab) since 1974 and a University of California at Berkeley physics professor since 1994. Smoot becomes Berkeley Lab’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, 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 grew our present universe.
“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 on the origin of the universe 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 the measurements they made using Differential Microwave Radiometers (DMR) which they designed and built, Smoot provided the strongest evidence yet that the Big Bang theory is correct.
As Smoot has 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. To this day, CMB radiation saturates all of space throughout the universe. In fact, at any given instant, every cubic meter of space is bathed in millions of photons of CMB radiation zipping along at the speed of light.
In 1976, Smoot was a key member of the team that found startling evidence in the CMB which 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. These findings 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,” Smoot said.
The new view of the universe created by this discovery required scientists to rethink the origin of the universe. Earlier studies had shown a virtually uniform CMB temperature — 2.7 degrees above absolute zero — which is consistent with the idea that in the early universe, matter was evenly distributed. With the finding that the universe is “lumpy,” however, scientists realized there should be minute temperature variations in the CMB radiation.
George Smoot was principal investigator of the differential microwave radiometer (DMR) experiment, which used three DMRs to measure minute temperature differences in the cosmic microwave background. Smoot began a search for these tiny fluctuations in 1974, submitting a satellite proposal to NASA to measure and map the CMB. 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 researchers — was ready to announce they’d found what had evaded scientists for decades.
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.
Smoot was born on February 20, 1945 in Yukon, Florida. His father was a hydrologist for the U.S. Geological Survey and his mother was a science teacher and school principal. He studied at the Massachusetts Institute of Technology (MIT) where he earned B.S. degrees in mathematics and physics in 1966, and received his Ph.D. in physics 1970. Although his doctoral thesis was on the decay of subatomic particles, Smoot jumped to the field of cosmology for his research because he saw it as a frontier of fundamental science ripe for exploration.
Smoot recalls that when he first started his career, cosmology wasn’t even considered a real science. “It was a fringe field,” he said. “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.”
For his CMB research, Smoot won wide scientific acclaim and a number of award and recognitions including most recently the 2003 Albert Einstein Medal. He has also written a popular book about cosmology and the CMB experiments entitled Wrinkles in Time.
The COBE team that Smoot headed was a large collaboration involving participants from Berkeley Lab, UC Berkeley, the NASA Goddard Space Flight Center, JPL, UCLA, MIT, and Princeton. In addition to Smoot, team members at Berkeley Lab included astrophysicist Giovanni De Amici, data analyst Jon Aymon, and Berkeley graduate students Charley Lineweaver and Luis Tenorio.
Berkeley Lab is a U.S. Department of Energy national laboratory located in Berkeley, California. It conducts unclassified scientific research and is managed by the University of California. Visit our Website at www.lbl.gov.
The Nobel Prize in Physics announcement can be read here: http://www.nobel.se/
For more information about George Smoot visit his Website at http://aether.lbl.gov/
For more details on the COBE project click here: http://aether.lbl.gov/www/EAA4536.pdf
For more information about the CMB map click here: http://aether.lbl.gov/www/cobeimp.html