The year was 1956. Barry Barish was a junior at Cal doing research at the California Radiation Laboratory, or Rad Lab (known today as the Lawrence Berkeley National Laboratory). When his professors were too busy to see him, he’d wander into the 184-inch cyclotron—a larger sequel to Ernest Lawrence’s fabled particle accelerators—invented at Berkeley and famous for blasting into existence an array of new heavy elements, including plutonium, berkelium, and californium. The control room of the cyclotron would be open, and there would be operator Jimmy Vale, methodically tuning the giant instrument. Barish would often stand behind the man, quietly observing his every movement.
“It always had this magic to it,” Barish recalled recently at a café near his home in Santa Monica. Vale was a technician who’d been working with the machine for years. He didn’t understand the physics, but, said Barish, he “knew, somehow, that if he changed this knob, he’d have to do something with this other knob. Well, that seemed a little strange to me, so I started learning what each knob did.”
So began Barish’s fascination with physics and, more specifically, with Big Science; that is, projects that pull together vast amounts of brainpower, money, and, typically, giant machinery, to probe deeper into the unknown.
Such a project is the Laser Interferometer Gravitational-Wave Observatory, or LIGO, a joint effort of CalTech and MIT first launched in the early 1980s. In September 2015, LIGO made the first ever detection of a gravitational wave—a tiny cosmic tremor born from the collision of two black holes 1.3 billion years ago. And in October 2017, Barish, a professor emeritus at CalTech, was awarded the Nobel Prize in Physics for his role in that discovery. Barish, who led LIGO from 1994 to 2006, shares the Nobel with colleagues Kip Thorne and Rainer Weiss. But all three laureates insist the prize also recognizes the work of more than 1,000 scientists and technicians in the LIGO community who helped make the discovery possible.
Albert Einstein predicted the existence of gravitational waves more than a century ago. According to his general theory of relativity, large objects and violent events in the cosmos distort the space around them, creating ripples that spread out across the universe at the speed of light.
“That’s what gravity is, in Einstein’s view,” explained Alex Filippenko, Berkeley professor of astronomy. “It’s not really a force; it’s that objects produce a warping in the shape of space.”
The effects of gravitational waves are extremely weak on Earth, however, and even Einstein doubted we’d ever be able to detect them. In fact, the job required two massive, ultrasensitive detectors (laser interferometers) spaced some 1,900 miles apart, which together comprise the second-biggest vacuum system in the world and have cost more than a billion dollars to build and operate.
By all accounts, Barish’s work—as much managerial as scientific—was at the heart of the massive project’s success. He first joined LIGO in the 1990s, when it was in disarray and at risk of losing funding. Barish, who had worked at CalTech since leaving Berkeley in 1963, was recruited to help resuscitate the project.
Barish had spent his life working in the Big Science milieu of high-energy physics and understood how to conduct experiments that stretched around the world. According to Gary Sanders, a former project manager at LIGO, that experience was exactly what was needed. “Those were skills that didn’t really exist in the gravitational wave community,” Sanders said. “It was like babies in an incubator—a number of very smart, very clever scientists who understood the principles of what they needed to do, but who didn’t really understand Big Science. Barry brought that to them.”
Barish taught the team how to collaborate, Sanders said, setting LIGO in the right direction for decades to come.
Growing up, Barish’s dream was to be an author. The dream faded somewhat after he was forced to read Moby Dick in high school and was traumatized by the long chapter on whale anatomy. “I thought, if this was what writing was about, then I’ll study science.”
A product of L.A. city schools, Barish came to Berkeley at 17, the first in his family to attend university. He started out in engineering because “science” sounded more like a subject than an actual occupation. But engineering felt too formalized to him. In drafting class, he’d lose points for the shape of his arrowheads. For a surveying course, he had to go around with these funny instruments, measuring campus buildings. For a bashful, self-conscious kid, it was too much.
Then there was chemistry, which Barish abandoned after a TA complained that he didn’t keep his beakers clean enough. “That was all I had to hear,” he said. “I’m not a good enough dishwasher to be a chemist.”
So Barish bungled into physics, and found a home.
At least, that’s the story he tells. His former fraternity brother, Marvin Cohen, a theoretical physicist at Berkeley and perennial short-lister for the Nobel, doesn’t think his old friend was quite as hapless as he makes it sound. “Even when we were undergrads, [Barry] always seemed to know exactly what he was doing. He was doing everything right.”
As for Barish’s self-professed shyness, Cohen said that although his friend was never one to stay up all night drinking and playing cards, neither was he a shut-in. “Barry was somewhere in the middle,” said Cohen. “He might have been shy and held back, but he had a pretty good balance of both.”
“Maybe I was lucky,” Barish says now. “I fell into the right things, and somehow became more social. But I was able to find a path, and it was a good one for me. I wasn’t the same person when I left Berkeley as I was when I came, at all.”
When Cohen and Barish were undergraduates at Cal, it was easy to gravitate towards physics, given the exciting discoveries emanating from the Rad Lab. “You had a feeling that this was the place and the time when all this new science was being done,” said Barish. “That’s why I wanted to stay as a graduate student.”
On some level, large-scale science was invented at Berkeley by Ernest Lawrence himself. His cyclotrons, which grew larger with each new iteration, called for very large teams of scientists and engineers, not to mention great stores of confidence and public support.
Barish, who earned his Ph.D. at Berkeley, never had an official advisor at the Rad Lab, but he got the department chairman, renowned physicist A. Carl Helmholz, to sign off on him. He liked the independence, and did his graduate thesis using leftover equipment from the cyclotron. After his degree, he stayed on for a post-doc, helping out with the Bevatron—a bigger and better particle accelerator, which Berkeley scientists used to create the antiproton, a discovery that won physicists Emilio Segrè and Owen Chamberlain the Nobel in 1959.
One night while Barish was working on the floor of the Bevatron, he was joined by CalTech professor Alvin Tollestrup, who offered Barish a research position at CalTech. Barish accepted and has been there ever since. But he still remembers Berkeley as the place where he found the loves of his life: his profession and his wife, Samoan, who earned her master’s degree in social work at Berkeley.
The couple dated as Barry was finishing his thesis, and Samoan was traveling to Palo Alto for a field placement. “It’s stressful to be students and to be with somebody,” she said. “But Barry is not a high-stress person. He’s not a worrier. I was. So it was a challenge.” They got married 11 months after meeting and are still together today.
For the past few decades, Barry and Samoan Barish have lived in Santa Monica, right by the beach. Barish rides his bike between Malibu and Venice in the mornings, about an hour’s ride, around sunrise—right before the boardwalk fills up with street vendors and artists. The diversity reminds him of Berkeley, which is why he loves it. “I’d rather meet somebody who’s an artist or philosopher than another engineer or physicist,” Barish said in his oral history for CalTech.
When he’s not working, Barish reads. He looks forward to meeting one of his favorite authors, Kazuo Ishiguro, this year’s laureate in literature, at the Nobel ceremony in Stockholm. Barish just has to rent a tux. “I’ve never owned a suit in my life.”
Barish became a professor at CalTech in 1966. He taught a range of classes, preferring to move around the field rather than focus on a single topic. It not only forced him to learn new material, but to learn it well.
He displayed a similar restlessness throughout his career. Barish was 58 when he joined LIGO, switching to gravitational waves after decades of research in high-energy particle physics, including a stint at the cancelled Superconducting Super Collider, and a ten-year detour to hunt for the magnetic monopole—the as yet hypothetical particle that contains either the north or south pole of a magnet, but never both.
“I still think in the back of his mind, he’s hoping someday he’s gonna look under some rock and it’s gonna be there,” said Cohen of his friend’s lifelong enchantment with monopoles.
Cohen, who has worked in condensed matter physics at Berkeley for most of his life, says that Barish’s career peregrinations are uncommon in the field. “There’s an old joke that you do your thesis for the rest of your life,” Cohen said. He compared Barish to “the bee going from flower to flower.”
“He’s kind of exploratory,” acknowledges Samoan Barish. “He feels he’s done enough with this, and he’s ready to move on.”
When Barish’s work with the Superconductor ended in 1993, CalTech jumped at the chance to have him move over to LIGO. The former director was out, and the project was floundering. LIGO had recently failed two important reviews, and the National Science Foundation had lost confidence in the project. Many scientists thought it was a “pie-in-the-sky type project that wouldn’t yield any conclusive results,” said Filippenko.
At first, Barish was hesitant to take the job. According to the oral history project, he wasn’t sure LIGO could be saved, or that he was the one to save it. He gave himself a month to study the project and then decide. When the month was up, he still wasn’t sure he could save LIGO—but he wasn’t convinced that he couldn’t, either, so he accepted.
“I think because he functions with a certain vision, he was able to see there’d be frustration, and that there’d be difficulties,” said Samoan Barish. “But he’s a good thinker. And that helps him both in his science and working with people.” Samoan is a practicing psychoanalyst. Asked if he leaned on his wife for help, Barish replies, “Absolutely. Maybe when I say I’m good at this stuff, it’s just because I have her.”
One of Barish’s key insights was that, brilliant as the CalTech and MIT teams were, they weren’t necessarily the very best minds in their fields. So in 1997 he launched the LIGO Scientific Collaboration, extending the team beyond the two laboratories and recruiting top theorists and data analysts from around the globe. To attract them to LIGO, Barish had to make sure they didn’t feel like “second-class citizens,” so he made the Collaboration independent of the lab, and gave it its own governance.
The observatory was under construction throughout the late 1990s, and Barish needed to somehow balance laboratory research, where scientists typically enjoy considerable freedom, with the administrative oversight necessary to make sure the project ran efficiently. That’s usually where large experiments go wrong, he said: People don’t manage to really blend the two. “I think there’s—and I hate to say it, as a scientist—but there’s a bit of an art to it.”
For guidance on how to better manage the project, he looked to civil engineering, studying how suspension bridges are built, hoping to emulate that kind of hierarchical structure within LIGO. “I never took a formal course, but I read the books,” Barish said. The Collaboration was another experiment for him to figure out. “We didn’t major in that—how to manage people,” said Cohen.
Barish says LIGO is still a flat organization—there are checks and balances within the group, and it is as democratic as possible. They vote on everything. “That’s why it takes us so long to put out a long article—1,000 people deciding on what adjectives to use.” Barish helped establish ground rules on how the team would publish papers, and who gets their names on them. A recent paper announcing the LIGO discovery of a neutron star collision had 3,500 authors, including astronomers and physicists from across the planet.
“That wouldn’t have been possible without someone like Barry,” said Sanders.
Today, after decades of development, LIGO is the biggest and most sensitive interferometer in the world.
Gravitational waves distort the shape of all objects in their path—things get stretched and squeezed this way and that, but by a microscopic degree. The scientific challenge of the last century has been to design an instrument powerful enough to capture those changes.
Each of LIGO’s detectors form a large right angle on the landscape, with two identical arm-like tunnels, each stretching 2.5 miles and housing a system of finely calibrated mirrors and lasers. One detector is in Hanford, Washington, and the other is about 1,900 miles away in a forest east of Baton Rouge. Having dual detectors is key. Because gravitational waves travel at the speed of light, scientists only take into account disturbances that happen at both facilities at nearly the same time.
When a gravitational wave passes by, LIGO’s arms contract or lengthen ever so slightly, which throws off its lasers by a tiny but crucial degree. The first wave LIGO detected shifted its instruments by about 1/1000 the length of a proton.
“We were overjoyed,” said Filippenko of the astronomy community’s reaction. “It was almost disbelief that this tiny, tiny variation in the length of these arms could actually be detected. This was a feat that was thought to be impossible, or at least extraordinarily difficult, a few decades ago.”
In the early days of LIGO, it was extremely difficult to predict all the technologies necessary for success. Barish’s strategy was to invest in good infrastructure, and to design LIGO in such a way that it could adapt to new technologies as they were developed. Its first iteration, Initial LIGO, was sort of a trial version meant to highlight what the problems were and to show the researchers a path forward. “When we learned what limited us, we licked our wounds and spent some period of months tackling those problems,” said Barish. “It’s a miracle that the funding agency kept with us, but they did, because we fulfilled our promise.”
For a period of about ten years, around 2004 to 2014, they developed bigger mirrors and better lasers and increased their sensitivity one step at a time. At the time, Cohen recalls, “Every time I saw Barry or talked to somebody working on this project, I’d say, ‘Do you guys really think you’re gonna get down and measure…’” Here Cohen trails off and pinches his fingers together, half a millimeter apart. “And they would say, ‘Well, you know, we just solved this, this, and this.’”
Barish helped the team choose the best way to deal with local disturbances—earthquakes certainly, but also vibrations from a passing truck. If not corrected for, these would cause a cacophony of false alarms in the detectors. Today, LIGO uses something called an active seismic isolation system to pinpoint external vibrations and cancel them out, similar to how noise-canceling headphones reduce extraneous noise.
According to Sanders, Barish was the first to realize that LIGO would need a much better laser than the one initially planned. He pushed for LIGO’s solid-state laser, a technology that could be scaled up to higher power as the instruments evolved. “Barry makes his evaluations and he states them, and people respect him for them because they know he’s thought about them,” said Cohen.
After significant trial and error, the team turned the machines off in 2010 to install the crucial upgrades. Four years later, they turned them back on, and within weeks LIGO started making detections.
For astronomers and physicists alike, it was a historic discovery, one that throws open a new window into the universe. Until now, the only clues we had about the early universe came from electromagnetic radiation. But gravitational waves are a qualitatively different phenomenon, Filippenko explained. “This is like Galileo first looking at celestial objects through an optical telescope back in December of 1609. That’s the kind of thing we’re talking about, 400 years later.”
Barish’s hope is that eventually we’ll have a network of gravitational wave detectors around the planet—and even in space—with which to study black holes and the mysteries surrounding them.
Ultimately, Barish says, gravitational waves may even realize the much-dreamed-of Grand Unified Theory. Currently, he explained, “we’ve got a beautiful theory of physics that works at very small distances, like particles, and we’ve got a beautiful theory of physics that works at very long distances, and never the twain shall meet.” The hope is that scientists will someday—probably not in our lifetime—be able to probe black holes for their quantum features: things like whether information about the particles swallowed by black holes is conserved or lost forever. That would get physicists closer to uniting the star-crossed theories once and for all.
For now, it’s completely theoretical. But, as always, Barish looks forward.