The LIGO interferometer in Livingston, Louisiana

With its 4-kilometer-long arms, the LIGO interferometer in Livingston, Louisiana, measures the stretching of space itself.

© Atmosphere Aerial

The long road to proving Einstein's biggest prediction

The quest to build the Laser Interferometer Gravitational-Wave Observatory (LIGO) was a story of ingenuity and persistence—and a decades-long scientific soap opera. In 1972, Rainer Weiss, a physicist at the Massachusetts Institute of Technology (MIT) in Cambridge, described how a device called an interferometer could detect ripples in spacetime. But LIGO, two giant interferometers in Livingston, Louisiana, and Hanford, Washington, didn’t take data until 2002. It finally scored a discovery on 14 September 2015, after a 5-year, $205 million upgrade.

The idea for LIGO gathered steam only after Kip Thorne, a theorist at the California Institute of Technology (Caltech) in Pasadena, took an interest, Weiss says. In the summer of 1975, the two attended a NASA workshop in Washington, D.C. Thorne had forgotten to book a hotel room, so Weiss took him in and the two talked all night. Thorne had doubted Weiss’s scheme and had even suggested in a textbook that it couldn’t work. Now, Weiss says, Thorne “flipped completely, saying what was in his book was wrong and becoming an advocate.”

Thorne saw LIGO as an opportunity for Caltech, and in 1979 he brought in Ronald Drever, a physicist at the United Kingdom’s University of Glasgow, who was working on an interferometer of his own. Thorne had asked Weiss to apply for the Caltech job, Weiss says, but Weiss’s record was too thin. “I sent him my CV,” he says, “and he calls me up and says, ‘Well, I got it, but it’s not all here. There must be some pages missing.’”

Weiss expected to work with Drever. However, Drever “wanted nothing to do with me,” Weiss says. “And it was not just me. He was going to come to America and build something by himself.” (Drever is in poor health and cannot give his side.) So for several years, Drever, Thorne, and Weiss all ran the nascent project together as a “troika,” building separate prototypes at MIT and Caltech until 1987, when the National Science Foundation (NSF) demanded that they combine their efforts under one director.

That director was Rochus “Robbie” Vogt, who had been provost of Caltech. He and Drever tangled, and Vogt kicked Drever out in 1992, changing the locks on his office. Still, Vogt advocated effectively for the project with Congress, and under his guidance the team wrote “a damn good proposal” for the twin LIGO instruments, says Michael Zucker, a LIGO physicist at Caltech. But Vogt didn’t see LIGO through to completion. “He envisioned a very small elite group pulling this whole thing off,” Zucker says. “That was misreading the environment.” In 1994, Caltech replaced Vogt with Barry Barish, a particle physicist and veteran of several big projects, who expanded the organization. “He put the project together in a way that was solidly run, and a lot of the personal squabbles stopped,” Weiss says. Only then did NSF approve $300 million for construction.

Meanwhile, Weiss couldn’t convince MIT to take a larger role in the project. Once, Weiss recalls, Gary Crawley, acting director of NSF's physics division, came to MIT to urge John Deutch, MIT’s provost from 1985 to 1990, to invest more in LIGO. After hearing Crawley’s plea, Deutch asked for a piece of paper, Weiss says. “He takes out a pen, scrawls a big zero on it, and shoves it under Crawley’s nose,” he says. Deutch says, “I don’t remember the drama of writing on a piece of paper,” and notes that other MIT administrators and physicists also opposed LIGO.

Through it all, Weiss continued to work on LIGO, even more so after he retired from MIT in 2001. “No scientific puzzle is too minor or beneath him,” says Nergis Mavalvala, a LIGO physicist at MIT. In recent years Weiss has led an effort to chase down and explain leaks in the enormous, 8-kilometer-long vacuum systems that contain the LIGO interferometers.

Over the years, Weiss suffered his share of frustration, says his son, Benjamin Weiss, a curator at Boston’s Museum of Fine Arts. “We used to hear about Drever and Vogt around the dinner table,” he says. But Weiss seems to have avoided bitterness, perhaps because of the way he dealt with disappointment. “Honestly, he worked more,” Benjamin says. After dinner—and a spell at the piano—Weiss would sit at the dining table with a legal pad, working after others were in bed. By all accounts he still does.

*Correction, 26 August, 12:27 p.m.: The story has been changed to correctly identify the NSF official who requested more support from John Deutch and that Deutch was MIT's provost at the time.