Storygram: Nicola Twilley’s “The Billion-Year Wave”

An artist’s conception shows two merging black holes similar to those detected by LIGO.

 


The following story diagram—or Storygram—annotates an award-winning story to shed light on what makes some of the best science writing so outstanding. The Storygram series is a joint project of The Open Notebook and the Council for the Advancement of Science Writing. It is supported in part by a grant from the Gordon and Betty Moore Foundation. This Storygram is co-published at the CASW Showcase.


 

Black holes, general relativity, and gravitational waves are not subjects you’d necessarily associate with high drama and excitement. Many readers, writers, and even some science journalists consider such hefty physics concepts boring, or too unrelatable or inaccessible. Physics—including astronomy, cosmology, theory, and the machinations of the universe at the very biggest and very smallest scales—is sometimes relegated to the science-writing sidelines. A handful of writers and readers watch it with interest, but it only earns a bright spotlight in the case of a momentous discovery or a gargantuan screwup. But in Nicola Twilley’s hands, high-energy physics is gripping, surprising, even funny—and that’s what makes her coverage of the first gravitational-wave detection so interesting. Almost every publication that covers science wrote about the discovery in February 2016, but no one else had exclusive access to the team beforehand. Twilley used her access, her curiosity, and her self-effacing manner to expertly convey the excitement and bewilderment of a discovery even Einstein thought would be impossible.

 


What Do You Want to See?

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Story Annotation

The Billion-Year WaveAt first I didn’t love the headline, but after reading through the story a couple times, I understood why the editors chose it. The wave provides the central action in the story, and a wave is an easy concept to grasp: Something in motion, propelled forward—just like the story itself.
After decades of speculation and searching, a signal came through. It promises to change our understanding of the universe.
By Nicola Twilley, The New Yorker
https://www.newyorker.com/tech/elements/gravitational-waves-exist-heres-how-scientists-finally-found-them
Published February 11, 2016
(Reprinted with permission)

 

 

Note: On October 3, 2017, the Royal Swedish Academy of Sciences announced that the Nobel Prize in Physics would be awarded to Rainer Weiss, Kip Thorne, and Barry Barish, three pioneers in the study of gravitational waves.

 

Just over a billion years ago, many millions of galaxies from here, a pair of black holes collided. They had been circling each other for aeons in a sort of mating dance, gathering pace with each orbit, hurtling closer and closer. By the time they were a few hundred miles apart, they were whipping around at nearly the speed of light, releasing great shuddersLove this choice of word. It’s much more evocative than “shakes” or “waves” or something similar; they would all sound flat here. And “shudder” has a sensual and even erotic connotation, so it works extremely well with the previous sentence’s description of a “mating dance.” of gravitational energy. Space and time became distorted, like water at a rolling boil.I am always struggling to find appropriate analogies for phenomena on ludicrous scales. I like this one because it’s so familiar. The fact that the story says “galaxies” in the first 10 words gives the story a certain context that might be unappealing to some readers, but by including in the first graf a quotidian example anyone can recognize, Twilley is signifying she intends this to be a story for anyone. In the fraction of a second that it took for the black holes to finally merge, they radiated a hundred times more energy than all the stars in the universe combined. They formed a new black hole, sixty-two times as heavy as our sun and almost as wide across as the state of Maine. As it smoothed itself out, assuming the shape of a slightly flattened sphere, a few last quivers of energy escaped. Then space and time became silent again.

The waves rippled outward in every direction, weakening as they went. On Earth, dinosaurs arose, evolved, and went extinct. The waves kept going. About fifty thousand years ago, they entered our own Milky Way galaxy, just as Homo sapiens were beginning to replace our Neanderthal cousins as the planet’s dominant species of ape. A hundred years ago, Albert Einstein, one of the more advanced members of the species, predicted the waves’ existence, inspiring decades of speculation and fruitless searching.There is so much packed into these few lines. Twilley covers untold eons with one brief mention of the most familiar characters from deep time. Absurd distance is chattily conveyed—50,000 years to travel the galaxy, clearly a long way. All of human culture and history culminate in this one genius and his weird idea, and while you might not have heard about his idea, don’t worry, because you do know him, so you can trust that it’s big. And we even get foreshadowing that we’re going to read about an incredible, improbable feat. Twenty-two years ago, construction began on an enormous detector, the Laser Interferometer Gravitational-Wave Observatory (LIGO). Then, on September 14, 2015, at just before eleven in the morning, Central European Time, the waves reached Earth. Marco Drago, a thirty-two-year-old Italian postdoctoral student and a member of the LIGO Scientific Collaboration, was the first person to notice them. He was sitting in front of his computer at the Albert Einstein Institute, in Hannover, Germany, viewing the LIGO data remotely. The waves appeared on his screen as a compressed squiggle, but the most exquisite ears in the universe, attuned to vibrations of less than a trillionth of an inch, would have heard what astronomers call a chirp—a faint whooping from low to high. This morning, in a press conference in Washington, D.C., the LIGO team announced that the signal constitutes the first direct observation of gravitational waves.The breathless pacing of these first two paragraphs obscures the dry fact that this heady physics story was announced from a conference room in Washington. Nicely done.

 

 

When Drago saw the signal, he was stunned. “It was difficult to understand what to do,” he told me. He informed a colleague, who had the presence of mind to call the LIGO operations room, in Livingston, Louisiana. Word began to circulate among the thousand or so scientists involved in the project. In California, David Reitze, the executive director of the LIGO Laboratory, saw his daughter off to school and went to his office, at Caltech, where he was greeted by a barrage of messages. “I don’t remember exactly what I said,” he told me. “It was along these lines: ‘Holy shit, what is this?’ ” Vicky Kalogera, a professor of physics and astronomy at Northwestern University, was in meetings all day, and didn’t hear the news until dinnertime. “My husband asked me to set the table,” she said. “I was completely ignoring him, skimming through all these weird e-mails and thinking, What is going on?” Rainer Weiss, the eighty-three-year-old physicist who first suggested building LIGO, in 1972, was on vacation in Maine. He logged on, saw the signal, and yelled “My God!” loudly enough that his wife and adult son came running.Sparing us the packaged quotes that everyone else had from the press conference—such as David Reitze’s “ladies and gentlemen, we have detected gravitational waves. We did it!” which appeared in multiple articles—Twilley immediately gives us high human drama, bringing home that this is a momentous thing. A curse word in The New Yorker, in only the third paragraph! I love that I can feel the confusion and excitement here, and I am eager to learn why these people are freaking out.

The collaborators began the arduous process of double-, triple-, and quadruple-checking their data. “We’re saying that we made a measurement that is about a thousandth the diameter of a proton, that tells us about two black holes that merged over a billion years ago,” Reitze said. “That is a pretty extraordinary claim and it needs extraordinary evidence.” In the meantime, the LIGO scientists were sworn to absolute secrecy. As rumors of the finding spread, from late September through this week, media excitement spiked; there were rumblings about a Nobel Prize. But the collaborators gave anyone who asked about it an abbreviated version of the truth—that they were still analyzing data and had nothing to announce. Kalogera hadn’t even told her husband.This is a nice personal detail that also serves as a signpost for the reader about what type of story this is. It’s not really a scientific-discovery story, it’s not a policy story, it’s not just a news story. This anecdote about Kalogera’s spouse, both personal and mundane, makes that clear.

LIGO consists of two facilities, separated by nearly nineteen hundred miles—about a three-and-a-half-hour flight on a passenger jet, but a journey of less than ten thousandths of a second for a gravitational wave.Twilley is very good at putting the wave first and foremost: It almost acts as a character, helping us walk through this story of its discovery. The detector in Livingston, Louisiana, sits on swampland east of Baton Rouge, surrounded by a commercial pine forest; the one in Hanford, Washington, is on the southwestern edge of the most contaminated nuclear site in the United States, amid desert sagebrush, tumbleweed, and decommissioned reactors. At both locations, a pair of concrete pipes some twelve feet tall stretch at right angles into the distance, so that from high above the facilities resemble carpenter’s squares. The pipes are so long—nearly two and a half miles—that they have to be raised from the ground by a yard at each end, to keep them lying flat as Earth curves beneath them.This is absolutely fascinating and the kind of detail I would probably not have thought to ask about, but will from now on. “Is your X infrastructure so long that you have to account for the curvature of the Earth?”

LIGO is part of a larger effort to explore one of the more elusive implications of Einstein’s general theory of relativity. The theory, put simply, states that space and time curve in the presence of mass, and that this curvature produces the effect known as gravity. When two black holes orbit each other, they stretch and squeeze space-time like children running in circles on a trampoline, creating vibrations that travel to the very edge; these vibrations are gravitational waves. They pass through us all the time, from sources across the universe, but because gravity is so much weaker than the other fundamental forces of nature—electromagnetism, for instance, or the interactions that bind an atom together—we never sense them.This is a really thorough and yet very digestible nut graf about one of the most complicated ideas anyone ever had—general relativity. What we perceive as gravity is actually a bending of space, which is pretty hard to get your head around. But almost everyone has seen a kid on a trampoline, or can at least imagine the brief warping of the fabric that results from the jump. Again, bringing in relatively universal, fun analogies works really well here, both for explanation and for pacing/tone. Einstein thought it highly unlikely that they would ever be detected. He twice declared them nonexistent, reversing and then re-reversing his own prediction. A skeptical contemporary noted that the waves seemed to “propagate at the speed of thought.”

If you’re enjoying this Storygram, also check out two resources that partly inspired this project: the Nieman Storyboard‘s Annotation Tuesday! series and Holly Stocking’s The New York Times Reader: Science & Technology.

Nearly five decades passed before someone set about building an instrument to detect gravitational waves.This sentence kicks off what ultimately leads to a long section of history, describing early efforts to build a gravitational-wave detector and why they failed. We go all the way back to the 1960s. Structurally, this kind of departure from the action can be hard to pull off. Leaving the news for, by my count, 2,080 words, a writer runs the risk of losing readers’ attention. Twilley chose to organize the story this way because she felt it was a story of a “modern pyramid,” in her words—an incredible feat decades in the making. Hearing about the long, checkered past of gravitational-wave science gives the ultimate discovery more heft. The first person to try was an engineering professor at the University of Maryland, College Park, named Joe Weber. He called his device the resonant bar antenna. Weber believed that an aluminum cylinder could be made to work like a bell, amplifying the feeble strike of a gravitational wave. When a wave hit the cylinder, it would vibrate very slightly, and sensors around its circumference would translate the ringing into an electrical signal. To make sure he wasn’t detecting the vibrations of passing trucks or minor earthquakes, Weber developed several safeguards: he suspended his bars in a vacuum, and he ran two of them at a time, in separate locations—one on the campus of the University of Maryland, and one at Argonne National Laboratory, near Chicago. If both bars rang in the same way within a fraction of a second of each other, he concluded, the cause might be a gravitational wave.

In June of 1969, Weber announced that his bars had registered something. Physicists and the media were thrilled; the Times reported that “a new chapter in man’s observation of the universe has been opened.” Soon, Weber started reporting signals on a daily basis. But doubt spread as other laboratories built bars that failed to match his results. By 1974, many had concluded that Weber was mistaken. (He continued to claim new detections until his death, in 2000.)

Weber’s legacy shaped the field that he established. It created a poisonous perception that gravitational-wave hunters, as Weiss put it, are “all liars and not careful, and God knows what.” That perception was reinforced in 2014, when scientists at BICEP2, a telescope near the South Pole, detected what seemed to be gravitational radiation left over from the Big Bang; the signal was real, but it turned out to be a product of cosmic dust.Ooh, liars and frustrations and mistakes. The BICEP2 findings were a huge controversy in science (and science journalism, as it happens) and it would have been tempting to rehash what happened there. But Twilley gives us just enough to grasp that this is a controversial field, and to convey the, um, gravity of what these people are claiming. Weber also left behind a group of researchers who were motivated by their inability to reproduce his results. Weiss, frustrated by the difficulty of teaching Weber’s work to his undergraduates at the Massachusetts Institute of Technology, began designing what would become LIGO. “I couldn’t understand what Weber was up to,” he said in an oral history conducted by Caltech in 2000. “I didn’t think it was right. So I decided I would go at it myself.”

In the search for gravitational waves, “most of the action takes place on the phone,” Fred Raab, the head of LIGO’s Hanford site, told me. There are weekly meetings to discuss data and fortnightly meetings to discuss coördination between the two detectors, with collaborators in Australia, India, Germany, the United Kingdom, and elsewhere. “When these people wake up in the middle of the night dreaming, they’re dreaming about the detector,” Raab said. “That’s how intimate they have to be with it,” he explained,Twilley originally wrote this section without this quote, and her editor, Alan Burdick, asked her to find something to help with the transition. As she tells it: “He was like, ‘we need something else here. I need a quote, I don’t know what it is, but find it.’ And I found that one, and he was like, ‘Exactly. That’s what was needed here.’ I thought it was a good transition without it.” I think this quote makes you realize that the people who built it, and work with it, have to be a special sort. Because Twilley used this fun quote up high, I am more inclined to be curious about the subject of all these dreams, which covers the next two paragraphs. to be able to make the fantastically complex instrument that Weiss conceived actually work.

Weiss’s detection method was altogether different from Weber’s. His first insight was to make the observatory “L”-shaped. Picture two people lying on the floor, their heads touching, their bodies forming a right angle. When a gravitational wave passes through them, one person will grow taller while the other shrinks; a moment later, the opposite will happen. As the wave expands space-time in one direction, it necessarily compresses it in the other. Weiss’s instrument would gauge the difference between these two fluctuating lengths, and it would do so on a gigantic scale, using miles of steel tubing. “I wasn’t going to be detecting anything on my tabletop,” he said.

To achieve the necessary precision of measurement, Weiss suggested using light as a ruler. He imagined putting a laser in the crook of the “L.” It would send a beam down the length of each tube, which a mirror at the other end would reflect back. The speed of light in a vacuum is constant, so as long as the tubes were cleared of air and other particles the beams would recombine at the crook in synchrony—unless a gravitational wave happened to pass through. In that case, the distance between the mirrors and the laser would change slightly. Since one beam would now be covering a shorter distance than its twin, they would no longer be in lockstep by the time they got back. The greater the mismatch, the stronger the wave. Such an instrument would need to be thousands of times more sensitive than any previous device, and it would require delicate tuning in order to extract a signal of vanishing weakness from the planet’s omnipresent din.

Weiss wrote up his design in the spring of 1972, as part of his laboratory’s quarterly progress report. The article never appeared in a scientific journal—it was an idea, not an experiment—but according to Kip Thorne, an emeritus professor at Caltech who is perhaps best known for his work on the movie “Interstellar,” “it is one of the greatest papers ever written.” Thorne doesn’t recall reading Weiss’s report until later. “If I had read it, I had certainly not understood it,” he said. Indeed, Thorne’s landmark textbook on gravitational theory, co-authored with Charles Misner and John Wheeler and first published in 1973, contained a student exercise designed to demonstrate the impracticability of measuring gravitational waves with lasers. “I turned around on that pretty quickly,” he told me.

Thorne’s conversionA word with religious connotations, which I find appropriate here for many reasons. People have dedicated their careers, and much of their lives, to making discoveries like the one made at LIGO. It seems appropriate to talk about it, and about their devotion, in terms that would also describe faith or a religious experience. It also reflects the grandeur of general relativity and the scales of the universe. Can you imagine how differently this would scan if she had instead written, “Thorne’s change of mind”? occurred in a hotel room in Washington, D.C., in 1975. Weiss had invited him to speak to a panel of NASA scientists. The evening before the meeting, the two men got to talking. “I don’t remember how it happened, but we shared the hotel room that night,” Weiss said. They sat at a tiny table, filling sheet after sheet of paper with sketches and equations. Thorne, who was raised Mormon, drank Dr Pepper; Weiss smoked a corncob pipe stuffed with Three Nuns tobacco. “There are not that many people in the world that you can talk to like that, where both of you have been thinking about the same thing for years,” Weiss said. By the time Thorne got back to his own room, the sky was turning pink.Give Twilley an award for these sentences. How many questions must she have needed to ask to get to these incredible gems? Read our Q&A for more on this scene.

At M.I.T., Weiss had begun assembling a small prototype detector with five-foot arms. But he had trouble getting support from departmental administrators, and many of his colleagues were also skeptical. One of them, an influential astrophysicist and relativity expert named Phillip Morrison, was firmly of the opinion that black holes did not exist—a viewpoint that many of his contemporaries shared, given the paucity of observational data. Since black holes were some of the only cosmic phenomena that could theoretically emit gravitational waves of significant size, Morrison believed that Weiss’s instrument had nothing to find. Thorne had more success: by 1981, there was a prototype under way at Caltech, with arms a hundred and thirty-one feet long. A Scottish physicist named Ronald Drever oversaw its construction, improving on Weiss’s design in the process.For the first time, I felt an inkling of boredom right here. It’s important to show the history behind this discovery, but I started to worry this section would bog down in the minutiae. Spoiler alert: It doesn’t!

In 1990, after years of studies, reports, presentations, and committee meetings, Weiss, Thorne, and Drever persuaded the National Science Foundation to fund the construction of LIGO. The project would cost two hundred and seventy-two million dollars, more than any N.S.F.-backed experiment before or since. “That started a huge fight,” Weiss said. “The astronomers were dead-set against it, because they thought it was going to be the biggest waste of money that ever happened.” Many scientists were concerned that LIGO would sap money from other research. Rich Isaacson, a program officer at the N.S.F. at the time, was instrumental in getting the observatory off the ground. “He and the National Science Foundation stuck with us and took this enormous risk,” Weiss said.

“It never should have been built,” Isaacson told me. “It was a couple of maniacs running around, with no signal ever having been discovered, talking about pushing vacuum technology and laser technology and materials technology and seismic isolation and feedback systems orders of magnitude beyond the current state of the art, using materials that hadn’t been invented yet.”Oh man, what a quote! It’s so friendly and accessible, showing Twilley’s interviewing skills as well as her care for the reader. But it’s also packed with physics ephemera, layering detail on detail to show how audacious this thing is and how impressive its success is. But Isaacson had written his Ph.D. thesis on gravitational radiation, and he was a firm believer in LIGO’s theoretical underpinnings. “I was a mole for the gravitational-wave community inside the N.S.F.,” he said.

In their proposal, the LIGO team warned that their initial design was unlikely to detect anything. Nonetheless, they argued, an imperfect observatory had to be built in order to understand how to make a better one. “There was every reason to imagine this was going to fail,” Isaacson said. He persuaded the N.S.F. that, even if no signal was registered during the first phase, the advances in precision measurement that came out of it would likely be worth the investment. Ground was broken in early 1994.

It took years to make the most sensitive instrument in history insensitive to everything that is not a gravitational wave. Emptying the tubes of air demanded forty days of pumping. The result was one of the purest vacuums ever created on Earth, a trillionth as dense as the atmosphere at sea level. Still, the sources of interference were almost beyond reckoning—the motion of the wind in Hanford, or of the ocean in Livingston; imperfections in the laser light as a result of fluctuations in the power grid; the jittering of individual atoms within the mirrors;“Jittering”—that sounds like quantum fluctuations! All elementary particles— photons, Higgs bosons, etc.—are also waves, in a corresponding quantum field, and quantum mechanics holds that all these particles/waves are constantly in flux, a notion called quantum fluctuations. That means, essentially, that they are always jittering around a bit. So using the word “jitter” here is a nice little treat for the uber physicsophile (like me). But Twilley handles it very deftly: Readers who don’t geek out on quantum physics can nonetheless appreciate this line as simply offering a great detail to show how hilariously sensitive LIGO is. distant lightning storms. All can obscure or be mistaken for a gravitational wave, and each source had to be eliminated or controlled for. One of LIGO’s systems responds to minuscule seismic tremors by activating a damping system that pushes on the mirrors with exactly the right counterforce to keep them steady; another monitors for disruptive sounds from passing cars, airplanes, or wolves.I’m sorry, what? Wolves? I read this sentence three times. My brain wanted to read cars, airplanes, or motorcycles. Cars, airplanes, or bikes. Cars, airplanes, or garbage trucks. The paw-steps of wolves? This is a shockingly incongruous and wonderful detail. It is so out of place that I can’t help but notice it, and laugh. It’s also an example (one of many) of Twilley’s deep reporting. Another reporter might have been satisfied with three types of vehicles, but she obviously pressed for more unusual examples.

“There are ten thousand other tiny things, and I really mean ten thousand,” Weiss said. “And every single one needs to be working correctly so that nothing interferes with the signal.” This quote demonstrates Twilley’s skill in deciding which details to share with readers. A few interesting nuggets help build our appreciation without bogging us down in, well, ten thousand details. When his colleagues make adjustments to the observatory’s interior components, they must set up a portable clean room, sterilize their tools, and don what they call bunny suits—full-body protective gear—lest a skin cell or a particle of dust accidentally settle on the sparkling optical hardware.

The first iteration of the observatory—Initial LIGO, as the team now calls it—was up and running in 2001. During the next nine years, the scientists measured and refined their instruments’ performance and improved their data-analysis algorithms. In the meantime, they used the prototype at Caltech and a facility in Germany to develop ever more sensitive mirror, laser, and seismic-isolation technology. In 2010, the detectors were taken offline for a five-year, two-hundred-million-dollar upgrade. They are now so well shielded that when the facilities manager at the Hanford site revs his Harley next to the control room, the scientist monitoring the gravitational-wave channel sees nothing. (A test of this scenario is memorialized in the logbook as “Bubba Roars Off on a Motor Cycle.”) This is great, because I thought the Harley example was a hypothetical. But no, it’s a real test they did, and of course they logged it. Excellent reporting. The observatory’s second iteration, Advanced LIGO, should eventually be capable of surveying a volume of space that is more than a thousand times greater than its predecessor’s.

Some of the most painstaking work took place on the mirrors, which, Reitze said, are the best in the world “by far.” Each is a little more than a foot wide, weighs nearly ninety pounds, and is polished to within a hundred-millionth of an inch of a perfect sphere. (They cost almost half a million dollars apiece.) At first, the mirrors were suspended from loops of steel wire. For the upgrade, they were attached instead to a system of pendulums, which insulated them even further from seismic tremors. They dangle from fibres of fused silica—glass, basically—which, although strong enough to bear the weight of the mirrors, shatter at the slightest provocation. “We did have one incident where a screw fell and pinged one, and it just went poof,” Anamaria Effler, a former operations specialist at the Hanford site, told me. The advantage of the fibres is their purity, according to Jim Hough, of the University of Glasgow. “You know how, when you flick a whiskey glass, it will ring beautifully?” he asked. “Fused silica is even better than a whiskey glass—it is like plucking a string on a violin.”Twilley says she wanted to spend time explaining the instrument, “because it’s insane.” This is another example of a section that could get bogged down in the weeds or a string of numbers, but it works well, in part because she writes about the machinery with such enthusiasm, and in part because she had such wonderful descriptions from the people who work on it. The note is so thin that it is possible for LIGO’s signal-processing software to screen it out—another source of interference eliminated.

 

A LIGO optics technician inspects one of LIGO’s core optics (mirrors) by illuminating its surface with light at a glancing angle. It is critical to LIGO’s operation that there is no contamination on any of its optical surfaces.

 

Preparing Advanced LIGO took longer than expected, so the new and improved instrument’s start date was pushed back a few days, to September 18, 2015. Weiss was called in from Boston a week prior to try to track down the source of some radio-frequency interference. “I get there and I was horrified,” he said. “It was everywhere.” He recommended a weeklong program of repairs to address the issue, but the project’s directors refused to delay the start of the first observing run any longer. “Thank God they didn’t let me do it,” Weiss said. “I would have had the whole goddamn thing offline when the signal came in.”OMG. Can you imagine? I love this admission and the drama it carries. See the Q&A for more on this.

On Sunday, September 13th,From billions of years in the lede down to the calendar date here, the use of days and dates changes the pacing of the story, just as we’re nearing the momentous hour. It helps build the tension. Effler spent the day at the Livingston site with a colleague, finishing a battery of last-minute tests. “We yelled, we vibrated things with shakers, we tapped on things, we introduced magnetic radiation, we did all kinds of things,” she said. “And, of course, everything was taking longer than it was supposed to.” At four in the morning, with one test still left to do—a simulation of a truck driver hitting his brakes nearbyagain, love the detail—they decided to pack it in. They drove home, leaving the instrument to gather data in peace. The signal arrived not long after, at 4:50 A.M. local time, passing through the two detectors within seven milliseconds of each other. It was four days before the start of Advanced LIGO’s first official run.

The fact that gravitational waves were detected so early prompted confusion and disbelief. “I had told everyone that we wouldn’t see anything until 2017 or 2018,” Reitze said. Janna Levin, a professor of astrophysics at Barnard College and Columbia University, who is not a member of the LIGO Scientific Collaboration, was equally surprised. “When the rumors started, I was like, Come on!” she said. “They only just got it locked!” The signal, moreover, was almost too perfect. “Most of us thought that, when we ever saw such a thing, it would be something that you would need many, many computers and calculations to drag out of the noise,” Weiss said. Many of his colleagues assumed that the signal was some kind of test.I can see why, given how many descriptions of tests we just read.

The LIGO team includes a small group of people whose job is to create blind injections—bogus evidence of a gravitational wave—as a way of keeping the scientists on their toes. Although everyone knew who the four people in that group were, “we didn’t know what, when, or whether,” Gabriela González, the collaboration’s spokeswoman, said. During Initial LIGO’s final run, in 2010, the detectors picked up what appeared to be a strong signal. The scientists analyzed it intensively for six months, concluding that it was a gravitational wave from somewhere in the constellation of Canis Major. Just before they submitted their results for publication, however, they learned that the signal was a fake.This is wild, and I really wanted to know more about it! Do other observatories do this? I want to talk to the guy who did the faking.

 

A LIGO technician installs a tube baffle to control stray light.

 

This time through, the blind-injection group swore that they had nothing to do with the signal. Marco Drago thought that their denials might also be part of the test, but Reitze, himself a member of the quartet, had a different concern. “My worry was—and you can file this under the fact that we are just paranoid cautious about making a false claim—could somebody have done this maliciously?”I admit this would never have occurred to me, but now I am worried too. Who would do this, and why? It seems like a weird aside, but it serves to show how seriously they took this discovery and how cautious scientists can be. he said. “Could somebody have somehow faked a signal in our detector that we didn’t know about?” Reitze, Weiss, González, and a handful of others considered who, if anyone, was familiar enough with both the apparatus and the algorithms to have spoofed the system and covered his or her tracks. There were only four candidates, and none of them had a plausible motive. “We grilled those guys,” Weiss said. “And no, they didn’t do it.” Ultimately, he said, “We accepted that the most economical explanation was that it really is a black-hole pair.”

Subgroups within the LIGO Scientific Collaboration set about validating every aspect of the detection. They reviewed how the instruments had been calibrated, took their software code apart line by line, and compiled a list of possible environmental disturbances, from oscillations in the ionosphere to earthquakes in the Pacific Rim. (“There was a very large lightning strike in Africa at about the same time,” Stan Whitcomb, LIGO’s chief scientist, told me. “But our magnetometers showed that it didn’t create enough of a disturbance to cause this event.”)I laughed out loud at this. A lightning strike in Africa, are you kidding me? I love that this happened, and that they knew about it, and I love that Twilley did such detailed interviews that she got this information. Eventually, they confirmed that the detection met the statistical threshold of five sigma, the gold standard for declaring a discovery in physics. This meant that there was a probability of only one in 3.5 million that the signal was spotted by chance.

The September 14th detection, now officially known as GW150914, has already yielded a handful of significant astrophysical findings. To begin with, it represents the first observational evidence that black-hole pairs exist. Until now, they had existed only in theory, since by definition they swallow all light in their vicinity, rendering themselves invisible to conventional telescopes.This is the first real description we get of the magnitude of the discovery. Invisible to conventional telescopes = this is an entirely new way of seeing the universe. Gravitational waves are the only information known to be capable of escaping a black hole’s crushing gravity.

The LIGO scientists have extracted an astonishing amount from the signal, including the masses of the black holes that produced it, their orbital speed, and the precise moment at which their surfaces touched. They are substantially heavier than expected, a surprise that, if confirmed by future observations, may help to explain how the mysterious supermassive black holes at the heart of many galaxies are formed. The team has also been able to quantify what is known as the ringdown—the three bursts of energy that the new, larger black hole gave off as it became spherical. “Seeing the ringdown is spectacular,” Levin said. It offers confirmation of one of relativity theory’s most important predictions about black holes—namely, that they radiate away imperfections in the form of gravitational waves after they coalesce.

The detection also proves that Einstein was right about yet another aspect of the physical universe. Although his theory deals with gravity, it has primarily been tested in our solar system, a place with a notably weak gravitational regime. “You think Earth’s gravity is really something when you’re climbing the stairs,” Weiss said. “But, as far as physics goes, it is a pipsqueak, infinitesimal, tiny little effect.”The six sentences that precede this quote are dense with lots of detailed astrophysics. As someone who traffics in these things, I’m curious about all of that, but I concede that others may not be. And that’s what makes this wondrous Rai Weiss quote so perfectly timed. It pulls the reader back to a more easily shared reality, without losing the meaning or consequence of the discovery. Near a black hole, however, gravity becomes the strongest force in the universe, capable of tearing atoms apart. Einstein predicted as much in 1916, and the LIGO results suggest that his equations align almost perfectly with real-world observation. “How could he have ever known this?” Weiss asked. “I would love to present him with the data that I saw that morning, to see his face.”Weiss is such a great character in this story; so lively and relatable, and Twilley uses his quotes to great effect.

Since the September 14th detection, LIGO has continued to observe candidate signals, although none are quite as dramatic as the first event. “The reason we are making all this fuss is because of the big guy,” Weiss said. “But we’re very happy that there are other, smaller ones, because it says this is not some unique, crazy, cuckoo effect.”

Virtually everything that is known about the universe has come to scientists by way of the electromagnetic spectrum.This line kicks off what may be the meatiest argument in this piece. We’ve spent a while now reading about all of LIGO’s superlatives, but it’s taken until now to bring home why it all matters. We’ve heard how LIGO is so super sensitive, how LIGO was controversial, how it might not even work! How the things it’s measuring might not even exist anyway! All of that is interesting for its own sake, but really, what makes LIGO special is that it was like opening an entirely new portal on the universe. It is hard to overstate how momentous this is for astronomy. I would have put this higher up in the story, or at least alluded to it somewhere earlier than this. I asked Twilley about it, and she explained it this way: “This is not a piece about the promise of gravitational waves, per se. This is a piece about that first detection and what it took to get there. … To be totally fair, if you were a physicist, there are things you would hope to read that were not in this piece. But that was not my target audience.” And that’s true. Four hundred years ago, Galileo began exploring the realm of visible light with his telescope. Since then, astronomers have pushed their instruments further. They have learned to see in radio waves and microwaves, in infrared and ultraviolet, in X-rays and gamma rays, revealing the birth of stars in the Carina Nebula and the eruption of geysers on Saturn’s eighth moon, pinpointing the center of the Milky Way and the locations of Earth-like planets around us. But more than ninety-five per cent of the universe remains imperceptible to traditional astronomy. Gravitational waves may not illuminate the so-called dark energy that is thought to make up the majority of that obscurity, but they will enable us to survey space and time as we never have before. “This is a completely new kind of telescope,” Reitze said. “And that means we have an entirely new kind of astronomy to explore.” If what we witnessed before was a silent movie, Levin said, gravitational waves turn our universe into a talkie.

As it happens, the particular frequencies of the waves that LIGO can detect fall within the range of human hearing, between about thirty-five and two hundred and fifty hertz. The chirp was much too quiet to hear by the time it reached Earth, and LIGO was capable of capturing only two-tenths of a second of the black holes’ multibillion-year merger, but with some minimal audio processing the event sounds like a glissando. “Use the back of your fingers, the nails, and just run them along the piano from the lowest A up to middle C, and you’ve got the whole signal,” Weiss said.This is a deftly handled example of how to use an analogy that works well even if it might not be universally relatable. I didn’t know what a glissando was, but who hasn’t run her fingers along a piano’s keys at some point?

Different celestial sources emit their own sorts of gravitational waves, which means that LIGO and its successors could end up hearing something like a cosmic orchestra. “The binary neutron stars are like the piccolos,” Reitze said. Isolated spinning pulsars, he added, might make a monochromatic “ding” like a triangle, and black holes would fill in the string section, running from double bass on up, depending on their mass. LIGO, he said, will only ever be able to detect violins and violas; waves from supermassive black holes, like the one at the center of the Milky Way, will have to await future detectors, with different sensitivities.

Several such detectors are in the planning stages or under construction, including the Einstein Telescope, a European project whose underground arms will be more than twice the length of LIGO’s, and a space-based constellation of three instruments called eLISA. (The European Space Agency, with support from NASA, launched a pathfinder mission in December.) Other detectors are already up and running, including the BICEP2 telescope, which, despite its initial false alarm, may still detect the echoes of gravitational waves from even further back in the universe’s history. Reitze’s hope, he told me, is that the chirp will motivate more investment in the field.

Advanced LIGO’s first observing run came to an end on January 12th. Effler and the rest of the commissioning team have since begun another round of improvements. The observatory is inching toward its maximum sensitivity; within two or three years, it may well register events on a daily basis, capturing more data in the process. It will come online again by late summer, listening even more closely to a celestial soundtrack that we have barely imagined. “We are opening up a window on the universe so radically different from all previous windows that we are pretty ignorant about what’s going to come through,” Thorne said. “There are just bound to be big surprises.”I think the ending is the only thing I wanted to change. I enjoyed Twilley’s voice so much in this piece that I would have preferred a written kicker, with some poignant observation or left-field detail gathered from her exquisite interviews, rather than ending on a relatively mild quote from Thorne. But after I asked her about this choice, I understood why she handled the ending this way. “I thought it was an incredible story of what it took for us to finally detect these things, and then you end the piece by opening up into what it might tell us, which we don’t know, because we’ve spotted something we have never been able to see before.” In that context, she argues, the “We don’t know” doesn’t seem so weak. Fair enough.

 


A Conversation with Nicola Twilley

Rebecca Boyle: The first thing I have to ask is how you got this story. As someone who covers this, and wrote about the most recent discovery of a gravitational wave last fall, I didn’t know about this in advance (I was also home with a baby, but still). It seems like you knew this was coming, or at least had some of the bones of the story reported, so I’m curious how that happened.

Nicola Twilley: I was just very lucky. I write for The New Yorker, and I don’t know exactly who, but someone on the LIGO team brought it to us. Rai [Weiss, who suggested building LIGO] and Kip [Thorne, a physicist and member of the LIGO team] are big New Yorker fans, so that might have been part of the decision process. But in any case, the folks at LIGO came to [Alan Burdick,] my editor at The New Yorker, who they knew from previously working together, and said, this is an exciting story. It’s not going to be public. There was the whole of, is there going to be an exclusive? Alan, who is an extremely wonderful science writer in his own right, decided that I would be the right person to write this story. That’s how it came to me.

The LIGO folks wanted it to be a print piece, obviously I wanted it to be a print piece, but I don’t think the editor at The New Yorker thought it should be a print piece. We couldn’t break the embargo, so there was lots of back and forth about timing and about whether it was an exclusive or not, that I wasn’t involved in at all. The first I knew of it was when I was back home in England for Christmas, and staying with my parents, and Alan emails and asks if I had a second, and we talked. I was sitting at the kitchen table with my dad, and I said, “Oh, The New Yorker wants me to do a piece on gravitational waves. Apparently they found them.” At that point, I had never heard of gravitational waves. I am not sure I should admit this, but there you go. I was like, “I don’t know …” (Adding this to my plate over the Christmas break, after what had been a crazy year, and I was on holiday back in England with everyone to see …) “It sounds like complicated physics, I don’t know.” My dad, who is a mathematician by training and understands these things, said, if they really found gravitational waves, that’s going to be a big deal, and I think you should do it. I was this close to saying no, which is ridiculous. He was right. I don’t often say that, but he was right.

RB: That’s interesting that you didn’t know much about gravitational waves before this. But had you written about physics before?

NT: I don’t consider myself a science writer. I consider myself a writer. One of the interesting things about being as ignorant of science as a discipline as I am is I tend not to understand the internal divisions science sets up. To me, sorting stories between the buckets of physics, biology, chemistry—I just can’t really do it. And I don’t really see the point. So, maybe I’ve written physics stories before, is the short way of answering that question. I’ve been writing for The New Yorker website, for the Elements section, and I would pick the stories that I thought were interesting. If you gave me a back catalog of my science writing and asked me to sort it into buckets, I would have a nervous breakdown. It’s funny, I didn’t think about it as a physics story. I thought about it as a space story. I was like, black holes, space, that’s exciting.

When I first spoke to Gabriela [Gonzalez, the spokeswoman for the LIGO collaboration], she was very charming and polite, but basically asked me, “How the hell are you gonna write this story? Because you don’t know anything about this.” I think—if I can give The New Yorker credit—their logic is, if I can understand this, and make sense of it, and find a way to tell it in a way that is interesting to me, that is going to reach a whole world of people who are like me and had no idea what a gravitational wave was until they woke up and heard the news that everyone was getting excited. I think that is the logic. Either that, or they are just hazing me.

I feel like there is this big mystique around science, that “There is no way you can possibly understand this.” And it’s like, oh, come on. People with a brain and the curiosity and the patience to listen, and scientists who are willing to communicate—you don’t have to have some special gift for it. You just have to be willing to do it. An ordinary person, with an ordinary level of intelligence and commitment to figuring stuff out and asking questions, can probably understand.

RB: I totally agree. A lot of scientists are really bad about that. And even sometimes other writers, who are like, “well, I came from the lab, and I think you have to have that knowledge to really understand.” And I don’t think so. As long as it’s cool, or interesting in some way, you can figure it out, and help people figure it out.

NT: Yes. I don’t want to claim I understand every nuance, because clearly I don’t. But to have a great story that shares the significance of the findings, often you don’t need that nuance or lab experience. You can still get it right. And The New Yorker fact-checkers really help with that, too.

RB: When you decided to do this, or I guess when your dad convinced you it was worth your time, at what point did you realize that, whoa, this was a big deal?

NT: I think almost right away. I think that’s one of the reasons I like writing these stories. I hated science in school, and now here I am with the chance to have these conversations. I mean, you are talking to Kip Thorne or Rai Weiss and they are explaining these things, and it’s just amazing. Straightaway, it’s amazing.

I had points of relation to this, even from a non-science background. From a landscape art point of view, I’ve always been interested in, what can we measure, and what are our instruments, and how does that shape what we see? I’ve done artistic projects based on that philosophy. And then I have these amazing scientists telling me how they dreamed up an instrument that could be this sensitive, to detect something that people weren’t even actually sure was even there. So to me, it’s like, who wouldn’t be into this story? It’s a crazy story!

This was a lovely story to report, because everyone was so excited. Like genuinely effervescent with excitement. And I mean, of course, because this had been this quest, and they had found it. It’s the best moment! They hadn’t been able to tell anyone yet, but they could tell me. So it was really lovely to talk to everyone, because they were all so excited and they were just bubbling over with enthusiasm. I happily sacrificed my Christmas and New Year’s plans.

RB: How long did this take you to report? Were you wrangling international phone calls the whole time?

NT: The first I heard of it was December 19. The story came out February 11. It wasn’t even the fastest turnaround I feel like I’ve had to do. It was just this lovely window where they couldn’t talk to other people. They were working really hard on their paper and verifying the result, so they were still doing their due diligence. But at least they weren’t being besieged by other reporters. I ended up talking for several hours to most of the people—Rai, Kip, a lot more people I didn’t quote. They were really surprised that I wanted to talk to the person who had first seen the signal. He is the first person in the world to see this. It was a guy called Marco [Drago, an Italian physicist]. He was literally sitting in front of his computer, looking at the LIGO data remotely, and he saw the chirp. He was the person who saw it. To them, that wasn’t big, but I was like, of course, the first person to see this? It’s been traveling for a billion years, and Marco sitting in Hannover sees this? That’s exciting! That was such a fun interview. He, as opposed to the others, was so bemused about being the one who saw it. Him describing his moment of “I think I’ve seen this, I don’t know what to do,” was amazing. His literal words were, “It was difficult to understand what to do.” He knew what he was looking at but he couldn’t process it, and I thought that was an important moment for the audience.

RB: That anecdote, and the one about the person who was at breakfast, and others—as a reader, I really appreciated those moments, of just normal people who are like, “What the hell?” I appreciated that dose of humanity. Because otherwise it could be kind of a dry subject.

NT: That’s really good to hear. In the reporting stage, the scientists were so excited, that it was important to me—I felt like if I could capture even a fragment of their own excitement, and communicate that, that felt almost like the most important part of the story. I’ve never talked to scientists who were so excited.

RB: I wanted to ask you about the structure of the story. You leave the implications of the news for astronomy for a long time. Instead, you first give people a lot of background on the history of this idea and why the ability to finally detect gravitational waves is a big deal. How did you pace that, and did you worry about holding the tension through that section?

NT: That’s a great question. I feel like there are two answers. One is that New Yorker articles often do take a step back at that moment. That’s sort of house style. But also, oftentimes I can’t start writing until I know how I am going to start the piece. And oftentimes it will come to me when I’m in the shower, or running, or in the middle of the night. And for this, I realized, I am going to do this countdown. It will start a billion years ago and it will be really fun.

I had two editors for this piece. Alan was the print editor, so although he assigned me the piece, and gave me input, it wasn’t his piece, because it wasn’t in print. So I worked with Anthony Lydgate, who was until recently the editor for Elements. He was awesome. So I sent it in this structure to Alan and Anthony, and Alan was like, “Oh, a tick-tock, perfect!” What’s so funny is I thought I had invented it. I am definitely making myself sound bad here. Then I Googled “tick-tock” and it turned out to be a journalistic thing! I could have saved myself all this trouble! Of course I was undoubtedly informed by reading tick-tocks before, but I didn’t know that’s what they were.

But in terms of the pulling back, I liked the uncertainty, the fact that Einstein wasn’t even sure that [gravitational waves] existed. The fact that Weber had these false detections, I felt like it helped understand the gravity of this announcement, to have this kind of checkered past. And then I wanted to spend some time with the instrument, because it’s insane. I spent so much time talking to folks about the crazy, crazy business about this instrument, and bringing them up to their detection state, getting them good enough, basically. I wanted people to understand, you don’t just build a big hole in the ground. I wanted that scene between Rai and Kip. The checkered history, the incredible effort—it’s almost like building a contemporary pyramid. It takes literally 1,000 people and enormous effort. Then to get to two guys in a room, drinking Dr. Pepper and smoking a pipe, I liked that. Oftentimes you don’t get a moment like that in science, and since there was one, it felt fun to spend some time there.

I did think it was fabulous that Rai had wanted the thing to be offline. I thought that was a fun tease moment, to come back into the detection. It sort of had a nice flow. They are polishing the instrument, it’s not working, the date is pushed back, it’s endless problems, Rai wants to take the whole thing offline.

RB: And that’s when they get the signal—like, the next day.

NT: Exactly. Then you go into all the doubt. And the subcommittee, did someone spoof us? I didn’t get into what it can tell us. Because this is not a piece about the promise of gravitational waves, per se. This is a piece about that first detection and what it took to get there. That’s what I wanted to tell, for me, anyway. I thought it was an incredible story of what it took for us to finally detect these things, and then you end the piece by opening up into what it might tell us, which we don’t know, because we’ve spotted something we have never been able to see before. Until you spend some time pointing out why we could never see it before, the “We don’t know” seems a little weaker.

RB: I’m glad you mentioned the Dr. Pepper thing, because I wanted to ask about that—I love that scene.

NT: That was so funny too. I kept asking [Thorne], “What was it like? It was an all-nighter, were you drinking coffee?” And he was like, “No, I’m Mormon.” I was like, “Well gosh, what did you do, then? Were you chewing gum?” And he was like, “I would have been having Dr. Pepper. I always drank a lot of Dr. Pepper.”

They both were so focused on the science, but I wanted you to be able to picture the conversation too.

RB: Were they like, “You really want to know what I was drinking? What is wrong with you, lady?”

NT: Pretty much. But in an hour-long conversation with Kip, mostly about science, I pushed him once on the soda. I feel like you get away with one or two questions that are like that, per scientist, before they start getting annoyed with you.

RB: But it’s so funny that that’s the type of thing that stands out to people. It’s something you can totally picture in your mind—I can imagine these two guys at a table, and there are like, cans of stale soda around them, a smoky room. It gives so much more of a picture of what they’re doing than what they think in their heads. We can’t really see that, but we can imagine the soda cans.

NT: Yes, yes. And the whole kind of all-nighter aspect of it, when you think about Kip pounding Dr. Pepper. And it tells you so much about them. Kip is such a gentle, abstracted individual, so of course he wasn’t caffeinating or smoking. He was having Dr. Pepper, which is essentially a kids’ drink. And Rai is like this super funny, loud, super East Coast kind of guy who smokes a pipe. I felt like it was a tiny little window into their personalities, and how they would have been in the room with each other, which we can never know because we weren’t there. I can imagine Rai being forceful and pounding the table. And Kip is just a milder-mannered individual. I was hoping—and this is a lot to ask a can of Dr. Pepper to do for you—but I was hoping it would help give some sense of these two very different guys, but in that room that night, they came up with something.

RB: I want to ask a little more about the level of detail you have in here. I remember thinking when I read your story the first time, “Oh, well, she was obviously there.” Clearly, you visually saw this place, and had lots of information that you then could use to write a really detailed story about what it looks like at LIGO. But you were not there, so how did you pull that off? The description of what the facility is like under the ground, and what its long arms are like. What level of reporting did that require in interviews, or how much time did you spend reading papers about this thing?

NT: I’m so glad you felt like that; it makes me very happy. And I would love to go there someday. I was kind of bummed that I wasn’t able to, but with a web piece, there isn’t a travel budget. A lot of it was that I was really lucky that people gave me great descriptions. I forced people to explain it visually to me, because I couldn’t picture it because I am not a physicist. So I was like, tell me, if I was standing there, what would I see? That’s sort of the advantage of being an idiot. Someone who would have had a better idea of what a gravitational-wave detector should have looked like would not have done that. They might have been able to have a vague picture in their mind. But I didn’t have a vague picture in my mind—I had no idea.

It was also just lucky. People gave me great descriptions, like Jim [Hough, of the University of Glasgow], who was like, “You know how, when you flick a whiskey glass, it will ring?” He said [they] use silica that the mirrors hang from, and it’s better than a whiskey glass. I loved that! Now I’m picturing something.

I spoke to wonderful people. They are in love with their instrument, and they do dream about it, and they spend all their time working on it. I would ask them what their favorite bit of it is. They spend all day working on it, they must have a favorite bit. They love their instrument like it’s a Stradivarius.

I could have spent time working on the math and the processing that was done on the signal, and I didn’t. That was really important, and I’m sure there is a way to write about it really interestingly too. But to me, what got me excited was like, holy crap, these people spent decades building and tuning the most sensitive instrument for something they didn’t even know if they were going be able to see? It’s astonishing. In the world of limited word count, that’s where I wanted to focus.

RB: Is there anything you wish you could have kept in here that you had to cut, or looking back on it, that you would have changed?

NT: The motorbike sound came in and out, and I’m so glad it’s in. I don’t remember any extraordinarily painful things to cut. My failing as a writer, or among them, is the fact that if I can go long, I will go long, and I didn’t really have time to go long with this. And that was kind of a blessing. Usually I write way too long and then I have to come back to it, cool down a week later and realize how much is irrelevant, and then I lose it really easily. I’m not attached to it. I usually have to put it in and then take it out. And this time there just wasn’t enough time, so the timeline actually helped.

Because I did decide to focus on the detection, and this instrument, rather than all of the other science around it that I could have focused on—I didn’t have time. I didn’t have time to learn what kind of math they have to do to pull out the signal from the noise.

The only thing I was unhappy about was that it didn’t go into print, because I feel like Rai and Kip wanted to see it in print and they deserved it. It should have been a print piece, and I’m sad it wasn’t. I think it’s fair to say that it’s sometimes hard to sell the editor of The New Yorker on the value of a science story. I also think there was some difficulty around the date—if they were lifting the embargo, what would that mean for a print piece. But I will be forever grateful to Alan for giving me the story, and for Anthony’s editing, and all the fact-checking and copyediting, and also just how lovely Rai and Kip and Dave and Vicky were. I have never spoken to such lovely people. They were so overjoyed, and to have the chance to share in that excitement before other people—it was such fun.

 

Courtesy of Nicola Twilley

Nicola Twilley

Nicola Twilley is a frequent contributor to The New Yorker magazine and a co-host of Gastropod, an award-winning podcast about the science and history of food. She is at work on two books: one about refrigeration for Penguin Press, and the other on quarantine, co-authored with Geoff Manaugh, for Farrar, Straus and Giroux. “The Billion-Year Wave” was anthologized in the 2017 edition of The Best American Science and Nature Writing. Follow her on Twitter @nicolatwilley.

 

 

 

 

Courtesy of Rebecca Boyle

Rebecca Boyle

Rebecca Boyle is a freelance journalist based in St. Louis. She is a contributing writer at The Atlantic and a frequent contributor to FiveThirtyEight, Scientific American, and other magazines. She focuses on history and astronomy, and her story on the gravitational-wave detection of a merger between neutron stars was anthologized in the 2018 edition of The Best American Science and Nature Writing. Follow her on Twitter @rboyle31.

 

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