Nobelist George Smoot, whose satellite experiments validated the Big Bang theory, dies at 80

Physicist George Smoot told a packed press conference in 1992, “If you’re religious, it’s like seeing God.”

He was referring to the cosmic microwave background, which he and colleague John Mather imaged with NASA’s Cosmic Background Explorer (COBE), marking the first detection of the minute temperature fluctuations in the radiation surrounding us. That detection was a confirmation of the Big Bang theory — the idea that the universe was born in a rapid cosmic expansion nearly 14 billion years ago — and earned him and Mather the 2006 Nobel Prize in Physics.

Smoot, a professor emeritus of physics at the University of California, Berkeley, and an emeritus faculty senior scientist at Lawrence Berkeley National Laboratory, died on Sept. 18 in Paris of a heart attack. He was 80 and, since 2009, had been a physics professor at the Université Paris-Cité and an affiliate of the Laboratoire Astroparticule et Cosmologie (APC).

Detection of the CMB was a triumph of precision cosmology — the detailed measurement of the temperature of the universe that continues to reveal new details about the universe’s infancy and its evolution since.

According to an obituary posted by APC on Sept. 24, “Today cosmology is at the center stage of physics, due in no small part to this [Smoot’s] and subsequent measurements of the CMB. This discovery prompted many researchers to switch to cosmology. A host of experiments, from the ground, from stratospheric balloons and from space have now followed the pioneering COBE measurements.”

Smoot and Mather, who earned his Ph.D. in physics from UC Berkeley in 1974, together led the building and launch of the COBE satellite in 1989 in a highly competitive race to detect the signature of the primordial explosion that birthed the universe. According to the reigning theory of the origin of the universe, the Big Bang fireball 13.7 billion years ago filled the universe with heat that has since cooled to a mere 2.7 degrees above absolute zero. But the theory also predicted that the temperature should vary across the sky, though previous experiments had failed to detect any variation down to 1 part in 1,000

Mather’s instrument confirmed that the microwave background radiation matched perfectly the spectrum of colors that astronomers predicted if the universe formed in a fireball.

Smoot’s instruments went further, detecting fluctuations equivalent to 1 part in 100,000 in the 2.7 degree Kelvin microwave glow. These slight variations in temperature and density of the early universe grew over billions of years into the galaxies and clusters of galaxies we see today.

When Smoot announced the detection in 1992, the late Stephen Hawking called it the greatest scientific discovery of the century.

“Those measurements really confirmed our picture of the Big Bang,” Smoot said at the time. “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.”

Smoot, who had been at Berkeley Lab since 1971, was appointed to the UC Berkeley physics faculty in 1994. The Nobel Prize committee cited Smoot and Mather for “the discovery of the blackbody form and anisotropy of the cosmic microwave background radiation.”

In 2007, Smoot used $500,000 of his Nobel Prize winnings to help endow the Berkeley Center for Cosmological Physics.

As Smoot acknowledged on his website, the Nobel Prize “brought a new dimension to his life.” In addition to research and teaching, he began traveling the world as a speaker and commentator on science-related issues. He also appeared in cameos on the celebrated sitcom “The Big Bang Theory,” and, in 2008, was one of only two people to win the $1 million prize on the game show “Are you smarter than a fifth grader?”

“He was somebody who always enjoyed looking ahead to what was happening in the world and what was coming next,” said colleague Saul Perlmutter, a UC Berkeley professor of physics and himself a Nobel Prize winner for discovering dark energy. “He would come to your office and explain to you why you had to change something you were doing because of what was about to happen. Almost always, I had that feeling that he was right, but it was very hard to operationalize any of the advice!”

The APC obituary called Smoot a “larger than life character” who “revolutionized our understanding of the cosmos and placed cosmology on a firm experimental footing.”

Most recently, he had focused on applying basic physics discoveries to improve peoples’ lives, particularly in the fields of air quality and medicine. According to his website, Smoot “… sees his role to inspire and encourage smart young people, to set them off on the path to discovery.”

“He did really enjoy the question of how do you reach a public and how do you spread the excitement about science,” Perlmutter said.

Origins of COBE

George Fitzgerald Smoot III was born in Yukon, Florida, on Feb. 20, 1945. He graduated from high school in Ohio, but spent part of his childhood in Alaska with his father, a hydrologist for the U.S. Geological Survey. His mother was a science teacher and school principal. On Smoot’s website, he wrote that in Alaska he “discovered a new way of life more directly linked with nature and the juxtaposition to modern technology and understanding of mankind.”

He graduated from MIT with a dual major in math and physics and completed his PhD there in 1970 in the field of experimental elementary particle physics. He then moved to Berkeley Lab as a postdoc in the group of Luis Alvarez, a Nobel Prize winner and UC Berkeley professor of physics. Alvarez had become interested in experiments relating to cosmology, and Smoot followed in his footsteps, worked on the High Altitude Particle Physics Experiment (HAPPE), a stratospheric weather balloon designed to detect antimatter in cosmic rays. They were unsuccessful.

In 1973, Smoot changed his focus to studying the CMB, which had only been detected in 1964. He worked with Richard Muller, another member of the Alvarez group and now a UC Berkeley professor emeritus of physics, to develop microwave detectors that they flew on balloons to reach heights above much of the atmosphere. Their team eventually developed an instrument, called a Differential Microwave Radiometer (DMR), to detect differences in the CMB temperature in spots 60 degrees apart on the sky, which they flew aboard a U-2 spy plane. It worked, finding an imbalance in the temperature of the sky that implied our galaxy is traveling about 1 million miles per hour through the universe.

At the time, Smoot said, cosmology was a fringe field of study. “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.”

Particle physicists, who are used to measuring miniscule signals from the interactions of elementary particles, helped ramp up the precision of cosmological measurements, Perlmutter noted.

“George came from particle physics and along with several others brought a can-do style of experimental design to bear on cosmological questions, where they were working at more and more extreme conditions of size and energy,” Perlmutter said. “The drive for greater and greater precision to actually see the anisotropies in the cosmic microwave background, in some ways, led the way in precision cosmology.”

In 1974, he submitted a proposal to NASA to build a satellite to get the DMR instrument above the atmosphere to search for, measure and map even smaller temperature fluctuations, joining many competitors. His proposal was combined with two others and he began collaborating with Mather at NASA’s Goddard Space Flight Center, who served as project director. Fifteen years later, the COBE satellite was launched. Smoot’s team at Berkeley Lab involved more than 40 people, while the COBE satellite project included an estimated 1,000 individuals

After Smoot announced the discovery of the CMB anisotropies in 1992, he continued to work on experiments to refine the measurements, including as a collaborator on a third generation CMB anisotropy observatory, the Planck satellite. These experiments have refined maps of the CMB to the point that they now mark the first notch in a “cosmic ruler” used to measure the history of an expanding universe driven by dark energy.

He also helped found various research institutes around the world, including in South Korea, Spain and France. At APC in Paris, Smoot played an instrumental role in the founding of the Paris Center for Cosmological Physics and the opening of the endowment fund “Physics of the Universe” to attract top postdocs, according to the center’s website.

He took a keen interest in educating the younger generation, founding the “Teaching the Universe” program for secondary school teachers. He also created an internationally popular MOOC (Massive Open Online Course) called “Gravity!” with Pierre Binétruy.

Smoot also collaborated with journalist Keay Davidson to write a general-audience book, “Wrinkles in Time” (1994), about the COBE team’s work.

Among his awards were the 2006 Gruber Prize, given jointly with Mather, the 2003 Einstein Medal of Switzerland’s Albert Einstein Society, the 1995 Lawrence Award from the U.S. Department of Energy, the 1993 Kilby Award and the 1991 NASA Medal for Exceptional Scientific Achievement. He was a member of the National Academy of Sciences.

Smoot leaves behind a sister, Sharon Smoot Bowie, of New London, New Hampshire, two nieces, and his partner, Nóra Csiszár of Paris.