Astrophysicist and author Janna Levin has a good nose. In the late naughts, catching a rising swell of attention to Alan Turing as the centenary of his birth drew near, she wrote a novel that intertwined his life with that of logician Kurt Gödel, which she called, with a knack for alluring but sometimes twisty language, A Madman Dreams of Turing Machines. Sure, anyone could’ve looked up the date of Turing’s birth, but few would’ve guessed he’d soon be the subject of a major American film. A few years later, again with an anniversary looming, Levin decided to chronicle the decades-long effort to catch a new kind of wave, and she began interviewing major participants, visiting laboratories, and compiling an account to be published sometime in 2016, 100 years after Einstein predicted the existence of gravitational waves. It’s as if (pardon the illogical analogy) somebody had said in 1492, “Hey, I think I’ll go to the Bahamas in case any Europeans turn up.” On February 10 of this year, not many people knew of these waves; on the 11th, the world was set on its ear, so to speak, by the announcement that they’d been heard, and Levin’s book, already on its way to print, was simply rescheduled to come out in March. She didn’t know how the story would end; the entire book is written from the standpoint of an open question. But she was there with the backstory just when we wanted it.
As we’ve grown to expect of scientific discovery, the work involves immensities both large and small. The basic idea for the project dates back to the 1960s, when slide rules were still in common use. The leading figures in the tale are old men now or, in one case, passed on. Hundreds of others contributed; Levin lists all of them in the back of the book. The plot keeps repeating itself: think of something, try it; figure out another way, try that; think of something bigger, ask for money, build it; imagine improvements, work them in, try it. The cost has become enormous; a relatively early plan had a price tag comparable to some present-day Hollywood films, around $70 million, but that was in the 80s, and the total has since surpassed a billion dollars. The machines involved are basically yardsticks, but they’ve grown from something that’ll fit in a room, to a prototype that’s 40 meters on a side, to a fully functioning device whose arms stretch four kilometers—that’s not far short of the horizon to someone standing on the ground. The aim all along has been to detect a tiny sound—it has frequently been called a chirp—that began very long ago and very far away. As Levin puts it, “The signals are infinitesimal. The sources are astronomical. The sensitivities are infinitesimal. The rewards are astronomical.”
The scheme is fairly simple, and Levin sketches it early. As it occurred to Rai Weiss, it was “let’s measure gravitational waves by sending light beams between things.” Levin amplifies that: “Suspend mirrors…and watch them toss on the passing gravitational wave. Keep track of the distance between them and their motions will record the changing shape of spacetime.”
She’s usually deft at explaining the science. In its current form, the project uses two huge installations, one in Washington and the other in Louisiana. Why two? You want a second one “not only to confirm the detection…but also to ascertain the location of the sound. The utility of two detectors on the Earth is like the utility of two ears on the head.” But the heart of the story, for Levin, is elsewhere: it’s not the science but the scientists, their background, their strengths and weaknesses, how they think, the labs they work in, the way they work with others. For most of them, we get a good sense even of how they talk, for Levin has tried to let them speak for themselves, through recent conversations of her own as well as earlier interviews.
Rai Weiss considered studied engineering in undergraduate school at M.I.T. but found that physics had fewer requirements. He’s a restless tinkerer, an emeritus member of the project now but still likely to be found with his hands in the apparatus. You can sometimes hear him trying to fix his memories into words: of an all-night talk with Kip Thorne in 1975, he says, “We made a huge map on a piece of paper of all the different areas in gravity. Where was there a future? Or what was the future, or the thing to do?” (Levin’s quotations can sometimes seem diffuse, but they catch her subjects thinking on the fly.) Despite his taste for independent work in a lab, Weiss eventually becomes the one most determined to do what it takes, in terms of studies and proposals and concessions, to keep the project going and growing. He’s the one who went to the National Science Foundation, who took the idea into the realm of big science.
Much like Weiss and much unlike him is Ron Drever, an experimentalist from Scotland with a special skill for ingenious methods—he once achieved an important result from a device he built in his mother’s backyard. Drever has some sort of visual-intuitive sense that’s the envy of his colleagues; he can work something out with a diagram that Thorne could resolve only with lengthy calculations. But despite Kip’s last name, Drever is the thorny one, convinced of the rightness of his views, virtually incapable of accommodating others; eventually he’s fired from the project. And there are mysteries about this man. Why, since childhood, has he always required special attention? Why does Levin report that she has only heard his voice in recordings? She’s cagey about him, which is one of the things that keep you turning the pages.
And then there’s theorist Kip Thorne himself. He’s the persuasive charmer, the one who soothes and smooths over and reconciles; Levin says, “Kip could make you believe.” Thorne may be even more far-seeing than the others in this tale. Levin reports, “He went so far as to say that by…1962, it was obvious to him that gravitational waves must exist, although the debates would continue…for another twenty years.” (Though Levin doesn’t say so, Thorne has one thing in common with the great popularizer Carl Sagan: each helped shape a major Hollywood film—Contact in Sagan’s case, Interstellar for Thorne. Levin does mention the latter.) You get the sense that his appearance disarms people; Weiss, meeting Thorne for the first time, recalls, “He’s a delightful man, but he looked cuckoo, absolutely cuckoo.”
The supporting players are well drawn, too. There’s Joe Weber, another experimentalist and an embodiment of “almost.” Levin says, “He was Shackleton many times, almost the first: almost the first to see the big bang, almost the first to patent the laser, almost the first to detect gravitational waves.” Weber, who died in 2001, was also an almost tragic figure; hubris led him to push his claims of detection too far, and he ended up setting back a field he had helped pioneer. There’s Jocelyn Bell Burnell, an astronomer who “found the first four pulsars ever discovered by human beings” but who was omitted from the Nobel Prize for the work. And there’s Robbie Vogt, the first director of the Laser Interferometer Gravitational-Wave Observatory (LIGO for short), who learned as a child in Nazi Germany to hate authority; he’s the sort of person who would take an administrative job because he’s sure all the other candidates would be worse.
Levin is a mostly reliable narrator—maybe only a fussbudget will care that in World War II, no nuclear weapon was “carried in a fighter plane over a target.” But she’s an unreliable stylist; some of her prose could benefit from a detangling treatment. Whether or not you know the concept of a random walk, you may stumble over this, as did one of the book’s two New York Times reviewers: “Progress was as random as the walk of a shred of lint through hot air.” She tells us that a Soviet researcher made a speech “for which he was later denunciated.” She uses “conceded” when she means “acceded” and says “the upscale” when she means “the scaling up.” And, despite her efforts to keep the general public in mind, she leaves unexplained a few terms such as “stochastic.”
Anyone reading the book now will know that the search paid off. But Levin, writing before the results were announced, repeatedly stresses the uncertainty. She calls the quest “quixotic” at one point and says elsewhere, “Gravitational-wave detection was risky, controversial, technologically nearly impossible.” In a way, the long effort is reminiscent of something Norbert Wiener pointed out about the atomic-bomb project: until it was done, no one knew whether it could be done. Some people may wonder whether the results so far have been worth the cost, as others have no doubt wondered whether the Large Hadron Collider has been; Levin herself says, “LIGO also needs to do more to justify the investment versus rewards calculus. LIGO has to ‘do astronomy,’” by which she seems to mean that this project, and others like it now being built, can’t rest on their laurels but must continue to advance scientific understanding. Is the answer worth the price? For me, the idea that human societies must focus on A, B, and C and can’t do D until later, as well as the related idea that not doing D would somehow in itself advance A, B, and C, goes against a part of human nature and a part of human history, the part that says we do and we must figure out for ourselves how things work. Besides, though we’ve mostly moved beyond the Victorian spirit, we still vibrate to tales of Ulysses-like striving, as many of our superhero entertainments show. There’s something of grandeur and inspiration here; listen attentively and you’ll hear it.
I read an uncorrected proof that lacked Levin’s epilogue, which addresses LIGO’s first success, and am curious how she wrapped up this short (256 pages) yet sweeping tale. But the body of her text ends on a fine note:
Somewhere in the universe two black holes collide…maybe more than a billion years ago.… A vestige of the noise of the crash has been on the way to us since early multicelled organisms fossilized in supercontinents on a still dynamic Earth.… When I started to write this book, the sound reached Alpha Centauri.… As the sound moves through the interstellar space outside the solar system, the detectors will be operational.… [Finally,] someone…in the control room…might barely hear something that sounds different. A sophisticated computer algorithm will parse the data stream in real time and send a notification…and someone will be the first to look over the specs of the trigger and think calmly, “This might be It.”