George Smoot, an American astrophysicist who shared the 2006 Nobel Prize in Physics for capturing the first images of the universe in its infancy, died on September 18 at his home in Paris. He was 80. His brother-in-law, Jack Bowie, confirmed the cause of death was a heart attack. Smoot’s work provided the strongest evidence to date for the Big Bang theory and transformed cosmology into a precision science.
Dr. Smoot, along with his colleague John C. Mather, was awarded the Nobel Prize for their work using the Cosmic Background Explorer (COBE) satellite. The NASA mission precisely measured the cosmic microwave background (CMB), the faint afterglow of creation. The COBE results confirmed the universe began in an explosive, hot birth nearly 14 billion years ago. The team’s most profound discovery, announced in 1992, was the detection of minuscule temperature variations within this background radiation. These tiny ripples were the primordial seeds that grew into the vast clusters of galaxies that populate the cosmos today.
A Glimpse of Primordial Seeds
The primary mission of the COBE satellite, launched in 1989, was to study the remnant heat from the Big Bang. This radiation, known as the CMB, had been discovered in 1964 by Arno Penzias and Robert Wilson, who also won a Nobel Prize for their work. While the CMB appeared remarkably uniform, cosmologists predicted that if the universe began as a single point, there must be slight temperature variations, or anisotropies, corresponding to the initial clumps of matter that would eventually form galaxies. For decades, these variations remained elusive, their detection pushing the limits of technology.
Smoot led the team in charge of the Differential Microwave Radiometer (DMR), one of the key instruments aboard COBE. After years of painstaking data collection and analysis, his team found what they were looking for: temperature fluctuations of just one part in 100,000 in the 2.7-Kelvin radiation that bathes the universe. The discovery was a monumental achievement. At a press conference in 1992, Smoot famously remarked on the profundity of the image his team had produced, stating, “If you’re religious, it’s like seeing God.”
The Cosmic Background Explorer
Instrumentation and Collaboration
The COBE project was a massive collaboration involving more than 1,000 researchers, engineers, and scientists. Smoot shared the Nobel Prize with John Mather, the overall project scientist for COBE. While Smoot’s DMR instrument was tasked with finding the anisotropies, Mather’s instrument confirmed that the CMB spectrum perfectly matched the blackbody radiation curve predicted by the Big Bang theory. This provided a dual pillar of evidence for the theory. Smoot’s specific contribution involved leading a team of about 40 researchers dedicated to the DMR experiment.
From Balloons to Space
Smoot’s quest to find these cosmic ripples began long before the COBE launch. In the 1970s, he developed a differential radiometer that he mounted on a U-2 spy plane to search for CMB variations. This early work helped rule out theories that the universe as a whole was rotating. He first proposed a satellite mission to NASA in 1974 to measure and map the CMB with far greater sensitivity than could be achieved from Earth or with high-altitude balloons. After 15 years of development and advocacy, that proposal culminated in the successful launch of COBE.
A New Era of Precision Cosmology
The discovery of the CMB anisotropy was a watershed moment in physics. The Nobel Prize committee noted that the COBE project marked “the starting point for cosmology as a precision science.” Before Smoot and Mather’s measurements, cosmology was often viewed as a field rich in theory but poor in hard data. The COBE results provided a firm observational foundation, allowing scientists to test and refine models of the universe’s origin and evolution with unprecedented accuracy. By studying the size and distribution of the “wrinkles” in the CMB, cosmologists could deduce critical details about the universe, including its age, composition, and ultimate fate.
The findings spurred the development of subsequent, even more sensitive missions, such as the Wilkinson Microwave Anisotropy Probe (WMAP) and the European Space Agency’s Planck satellite, on which Smoot also collaborated. These missions have since mapped the CMB in much higher resolution, confirming COBE’s fundamental discoveries and ushering in what many call the “golden age of cosmology.”
Life and Legacy
George Fitzgerald Smoot III was born on February 20, 1945, in Yukon, Florida. His mother was a science teacher and his father a hydrologist. He earned dual bachelor’s degrees in mathematics and physics and a doctorate in physics from the Massachusetts Institute of Technology in 1970. He then moved to the University of California, Berkeley, and the Lawrence Berkeley National Laboratory, where he remained for the rest of his career. Since 2009, he had also been a professor at the Université Paris-Cité.
Smoot was known as a charismatic and original thinker who was deeply passionate about his work. Following his Nobel win, he used $500,000 of his prize money to help establish the Berkeley Center for Cosmological Physics to support future research. He also made several television appearances, including on “The Big Bang Theory” and “Are You Smarter Than a 5th Grader?”, where he won the $1 million prize. His work fundamentally changed our understanding of the cosmos, providing a direct view of the universe at the moment of its birth.
