Episode 10: Barry Barish discusses gravitational waves, LIGO, and the scientists who made it happen
May 3, 2016//
In many respects, Barry Barish is the quintessential scientist: soft-spoken and modest, he is also completely dedicated to the pursuit of pure science. Barish is currently the Linde professor of physics at Caltech. He’s a leading expert on gravitational waves, and his leadership and advocacy to the National Science Foundation about the need for LIGO (laser interferometer gravitational wave observatory) played a key role in convincing the NSF to fund it. Barish was the principal investigator of LIGO in 1994, before becoming its director in 1997.
The pay-off of Barish’s effort and the NSF decision was huge: Last February, Barish and other scientists announced to the world that they had detected gravitational waves four months before, marking the first ever direct detection since Albert Einstein predicted the existence of gravitational waves in 1916. The proof came via a chirping sound—played below in this interview—which was the sound-wave translation of the merger of two black holes more than a billion light years away.
Barish talks to STEM-Talk host Dawn Kernagis and co-host and IHMC Director Ken Ford about the history of Einstein’s theory and the science that later ensued to set up this significant discovery. He also talks about the scientists who made it happen.
Barish gave an IHMC lecture in 2009 entitled “Einstein’s Unfinished Symphony: Sounds from the Distant Universe”
Here is a link to the LIGO press conference on the gravitational waves detection: https://cds.cern.ch/record/2131411
1:36: Audio of “the chirp” signaling the detection of a gravity wave emanating from two black holes merging one billion light years away.
2:57: Ford reads a five-star iTunes review from CCPABC: “Love the science-based discussions, which also includes the interviewers, who also know and understand science, a rarity amongst podcast hosts. Love the funny comments along the way. For example, “Stay curious my friends.” And “Walk into a Walmart to see epigenetics at work.” Outlines (show notes) are also helpful for those of us who want to listen to specific sections again for better understanding.”
3:37: Dawn recaps Barish’s career, calling him a “leading light in several areas of physics.”
4:04: In October 2002, Barish was nominated by President George W. Bush to serve on the National Science Board of the NSF. Ford was also on the board. “We immediately connected and worked on the NSB for six years,” Ford said.
5:15: Barish discusses his upbringing and initial interest in science. Born in Omaha, Nebraska, to parents who had not gone to college, Barish said, “I was probably a scientist before I knew it.” The first science question he asked his father was why ice cubes float on water. His father’s answer didn’t satisfy him. “His answers never satisfied me, which I think is kind of the scientific mind.”
6:36: Ford, Kernagis and Barish recall one of their first scientific questions on why the sky is blue.
7:20: Barish grew up around Hollywood, California. “The furthest horizon I could see was Caltech, and that is where I thought I would go to college.” He went to Berkeley instead because he could start mid-year there, and he immediately fell in love with it — and a young girl.
8:55: Barish started as an engineering student, but he liked neither his surveying course nor his engineering drafting course. “By default, I ended up in physics. It’s where I belonged because physics has been great for me.”
11:15: In 1905, Einstein discovered: E=mc^2; and the theory of special relativity: “These solved some long-standing problems in physics in no time at all.”
11:42: In 1915, Einstein came up with the theory of general relativity, which was an extension of the theory of special relativity that added accelerations instead of just velocities.
13:30: In Newton’s theory of gravity, there’s instantaneous action at a distance: When the apple falls, you see it immediately. When something happens in space (a star collapses), it takes light years for the information to get to us. The concept of instantaneous action and distance doesn’t really work for gravity at long distances and Einstein probably realized that.
14:10: In early 1916, Einstein realized in analogy to the theory of electromagnetism, that there would be gravitational waves, but he didn’t prove it very well. He did it by analogy instead of fundamental proof.
14:45: In 1920-21, a British physicist went to the Southern hemisphere and saw a phenomenon that wouldn’t happen in Newton’s theory of gravity, but did in Einstein’s: He had predicted the bending of light: eclipse of sun and as stars went behind the sun their light bent at exactly the amount that Einstein had predicted. “That’s actually what made Einstein a household name.”
15:20: Einstein predicted gravitational waves as a concept, but thought they were too small to ever detect. “Of course that’s because one hundred years ago, he couldn’t envision the types of technologies we would develop.”
16:06: In 1960, Joseph Weber, a student of John Wheeler’s at Princeton decided to look for gravitational waves, using a very clever technique: He made a big cylinder of aluminum, of a diameter equal to his own height and two-three meters long, and if you banged it with a hammer, it rang at some frequency. If a gravitational wave came through, it would ring. “He’s responsible in a very positive way, for starting this field.”
17:10: That student, who turned out to be a “good technologist, but a lousy scientist,” Barish said, wrote a paper touting his own discovery of gravitational waves, which was shot down. “He was bitter that people didn’t believe that he saw gravitational waves, yet he was the one who started the field.”
17:55: A gravitational wave, if it goes through you, stretches you in one direction, and squashes you in another. “It’s like one of these mirrors in an amusement park, where you get taller and thinner if you look at one, and shorter and fatter if you look at the next one. So you get taller and shorter, thinner and fatter at the frequency of a gravitational wave.”
18:25: Barish discusses the creation of interferometers. There are two: in Hanford, Washington (near a Dept of Energy site), and in a pine forest of Louisiana.
20:53: They proposed a final decision to the NSF in 1994. It was the biggest thing at that time that the NSF had ever considered taking on.
21:08: Barish says they made a technical mistake in calling it LIGO, which stands for laser interferometer gravitational wave observatory. The word ‘observatory’ is not a physics word. It is word used by astronomers for their telescopes, and the astronomers thought it was a crazy project.
22:09: “In order to try to find something new, you pretty well have to do something that’s risky, and pushes the technology and pushes the ideas that you have, and oftentimes it doesn’t work. So taking on high-risk, high pay-off projects is something the NSF uniquely does.”
22:30: “Increasingly high-risk projects are getting harder to support. I’m not sure what we got approved in 1994 would get approved by today’s NSF.”
23:00: Ford, referring to the period when Advanced LIGO was under review by the National Science Board, said, “At the time, I was chairing committee on programs and plans (CPP), and certainly I got an earful about why it was a dreadful idea.”
23:50: Barish commends the NSF for taking on a very expensive, high-risk project—and staying with it for 22 years— despite the fact that it had had a certain amount of controversy, and “especially despite the fact that we had not much to show for all those years.”
24:13: The total cost of LIGO was 1.2 billion dollars.
24:36: Barish talks about the major players in getting LIGO up and running: Princeton’s John Wheeler, the father of the general relativity field after Einstein’s generation, and his student Kip Thorne.
26:45: A robust R&D effort started in Europe. At MIT, Ray Weiss assigned his students the idea of doing interferometry.
29:00: Ron Drever from Scotland was brought to Caltech to work on gravitational waves experimentally. MIT and Caltech worked on them together, but Ray was analytical, Drever was intuitive, and they didn’t get along.
30:23: By 1990, a proposal was turned into the NSF, which stimulated the NSF to ask lots of questions.
30:50: The original idea was that the two interferometers would be near the Edwards Air Force Base in Southern California; and in southern Maine. The NSF said that there should be a national competition to decide the respective locations, which as a result, ended up being Washington state and Louisiana.
32:40: “The plan was to make it evolutionary: Build the infrastructure to be flexible enough that we could keep evolving the interferometers as we learned how to do the technology.” That was not the way projects had been done before.
34:37: At a certain point, Barish says that the project got in trouble…it was being done by scientists alone in labs who didn’t get along that well together.
35:20: The NSF was right on the verge of canceling the project when the super collider was canceled by Congress in October of 1993, and around Christmastime, the head of Caltech’s physics department and its president asked Barish to take it over. Within a year, he had hired a lot of good people who were available from the demise of the super collider.
37:00: In 1994 Kip Thorne and Barish testified before the NSF, which is normally done by project managers. The NSF approved LIGO.
37:37: “Continuing with a very strong R&D program through the years has been key to its success. We didn’t over-spend, we met time scale goals. Even though we hadn’t yet made any good science, we managed to satisfy all the goal posts …. They never lost confidence in us.”
38:28: Ford says the detection of gravity waves is a wonderful story: “from Einstein’s initial discovery to the long march of scientists standing on each others’ shoulders…. All of this was for no commercial, military or geopolitical purpose. It was just to know, driven by human curiosity.”
39:08: Barish says, “It’s really emblematic of what the NSF should be about, and of what pure science should be.”
40:09: Barish says we’ve heard the first “beat” or chirp in “Einstein’s Unfinished Symphony” (referring to the title of his IHMC lecture.)
42:22: “Everything we know about our universe comes from the electromagnetic spectrum: looking at visible light, infrared, ultraviolet, x-rays. What we know about the universe has grown tremendously as we move beyond just the optical spectrum.”
43:19: However, all phenomena don’t emit light…black holes don’t emit light. “The two objects we saw were about thirty times the mass of our sun, and about the size of Los Angeles greater area.”
44:20: “It’s going to take years to make more sensitive detectors…both in terms of the future of astronomy/astrophysics and the future of studying the most fundamental things in physics itself…all of this just has a really bright future.”
45:00: Interferometers need to be in extremely quiet environments. But in the Washington location, there were wind generators 10-15 miles away that shook the earth. In LA, huge pipes carried oil from Southern states to Northern states, and they could “hear” the rumbling below.
46:16: “We start with an environment that’s pretty quiet, and then we have to isolate ourselves from everything that’s noisy…but no matter how much we work at it the earth below us shakes at low frequencies, and we have to minimize that.” To do that, they created “a very fancy set of shock absorbers.”
48:24: Barish talks about the international linear collider. “I’m perennially a graduate student; I’m most excited when I’m learning something new.”
52:35: Barish talks about how he pulled together the best physicists from around the world to work on the international linear collider.
55:20: When talking about the likelihood of the international linear collider actually being constructed, Barish said that if it were to be built, that it would probably be in Japan and that the current situation is that the Japanese government has been conducting “super due diligence.”
56:33: Barish discusses being a junior science working with Friedman, Kendall and Taylor (SLAC physicists who won the Nobel Prize for investigations on the deep inelastic scattering of electrons on protons and bound neutrons). Barish turned down the opportunity to work with them on the project well before their award-winning work.
58:15: Barish talks about his lifelong love of storytelling and fiction.
1:00:46: Dawn thanks Barish for the interview.
1:01:15: Dawn and Ken wrap about the interview. Ford says, “LIGO is a story of courage, curiosity, and intellectual audacity that will be noteworthy for a very long time.”
1:02:10: Dawn and Ken sign off.