Imagine being deaf from birth and suddenly, overnight, being able to hear. For all of history we have been able to “see” the universe. On 14 September 2015, we were at last able to “hear” it. Physicists in the US picked up “gravitational waves” – ripples in the fabric of space-time predicted by Albert Einstein almost exactly 100 years ago. Our media have a tendency to overhype. But a good case can be made that the detection of the voice of space is the most important development in astronomy since the invention of the telescope in 1608.
Janna Levin describes what happened on 14 September 2015 in a brief addendum to Black Hole Blues (only a superhuman could have written an entire book since the announcement of the discovery on 11 February of this year). In a galaxy far, far away, at a time when the Earth boasted nothing more complex than a bacterium, two monster black holes, locked in a death spiral, whirled about each other one last time. As they kissed and became one, a tsunami of tortured space-time surged outwards, so violent that for an instant its power output was 50 times greater than all the stars in the universe put together.
Space-time is a billion billion billion times stiffer than steel, which is why it can be vibrated significantly only by the most violent cosmic events, such as black hole mergers. But those vibrations, like ripples spreading on a lake, die away rapidly. And the gravitational waves that reached Earth on 14 September 2015, having travelled for 1.4 billion years across space, were mind-bogglingly tiny.
Enter the Laser Interferometric Gravitational-Wave Observatory (Ligo), in essence a couple of giant 4km rulers made of laser light – one at Livingston in Louisiana and the other at Hanford in Washington State. At 5.51am Eastern Daylight Time on 14 September 2015, first the Livingston then, 7 milliseconds later, the Hanford rulers repeatedly expanded and contracted by 100-millionth the diameter of an atom. As Levin so eloquently puts it: “The signals are infinitesimal. The sources are astronomical. The sensitivities are infinitesimal. The rewards are astronomical.”
In Black Hole Blues, Levin tells the remarkable story of the Ligo project – a 50-year technological odyssey – and the remarkable people who have made it happen. She excels in conveying the personalities of the scientists and their professional and personal struggles. She tells of Rochus “Robbie” Vogt, project director from 1987 to 1994, whose traumatic experiences as a press-ganged 15-year-old German soldier in 1945 drove a fury in him never again to accept authority. Perhaps it is no surprise, then, that, despite his contribution to Ligo, he was eventually fired. Levin also writes of Joe Weber, who built the first gravitational wave detector – a 2m long, 1.4 tonne aluminium cylinder designed to ring like a bell when hit by a space-time ripple. His spurious claim that he had detected gravitational waves in the 1970s destroyed his scientific reputation but kick-started the whole field.
But Levin’s story is really of three men – the “troika” – who were the principal driving force behind Ligo. The first is Kip Thorne, the hippie-dressing theorist famous for his black hole wagers with Stephen Hawking, most of which he has won. The second is Rainer “Rai” Weiss, the experimentalist who graduated from building hi-fi sound systems in New York in the 1940s to building sound systems for listening to the cosmos. Too busy tinkering to write the necessary papers to shore up a scientific career, Rai has walked every inch of the Ligo tunnels, personally evicting wasps, rats and other intruders. But, without doubt, the most complex and tragic member of the troika is the Scottish physicist Ronald Drever.
I was a physics graduate student at the California Institute of Technology – co-constructor of Ligo along with the Massachusetts Institute of Technology – and I remember once going to a talk given by Drever at Caltech. What struck me most about the short, dumpy man was that he carried his papers in two supermarket carrier bags and that his overhead projector transparencies were covered with greasy fingerprints and tea stains. That this man was needed by Caltech – ranked the number one university in the world in the Times Higher Education World University Rankings since 2013 – is testament to his genius.
Neither Thorne nor Weiss doubted Drever’s brilliance (while Thorne would get an answer to a technical question after pages of careful calculation, Drever would somehow reach the same conclusion with a simple diagram). It was just that the Scottish physicist was constitutionally incapable of sharing control of the project. “He never lived in this world,” Thorne told Weiss as he tried to persuade him that Ligo was impossible without Drever. “He [Thorne] had this child on his hands,” said Weiss. “This brilliant child.”
In 1997, Drever was kicked off the project. But according to Levin he remained in Pasadena, close to Caltech, confused and saddened by events. An unworldly man who never married and had no real friends in the US, he finally succumbed to dementia. The tale Levin relates of Caltech faculty member Peter Goldreich taking the bewildered Drever to New York’s JFK airport and putting him on a plane back to his brother in Glasgow is heartbreaking. Drever now lives in a care home in Scotland. To the Nobel committee, which no doubt at this moment is considering the three names of the troika, I have just one message: Hurry up.
Ligo is a technological marvel. At each site there are actually two tubes 1.2m in diameter, which form an L-shape down which a megawatt of laser light travels in a vacuum purer than space. At each end, the light bounces off 42kg mirrors, suspended by glass fibres just twice the thickness of a human hair and so perfect that they reflect 99.999 per cent of the light. It is the Lilliputian movement of these suspended mirrors that signal a passing gravitational wave. So sensitive is the machine that it was knocked off-kilter by an earthquake in China. “It whirs with the tidal pull of the celestial bodies, the grumbling of a still-settling earth, the remnants of heat in the elements, the quantum vibrations and the pressure of the laser,” writes Levin.
A technological marvel Ligo may be, but not everyone thinks it is what it seems. Levin tells of a man on a flight into Baton Rouge, Louisiana, who informed the Ligo scientist in the seat beside him that the secret government facility below them was designed for time travel. “One of the arms brings you to the future,” he confided; “the other sends you to the past.”
With the success of Ligo, we stand at the dawn of a new era in astronomy, Levin says in her excellent book. It is as if a deaf person has gained a sense of hearing, but at present that sense is crude and rudimentary. At the very edge of audibility, they have heard a distant rumble of thunder. But they are yet to hear birdsong or a piece of music or a baby crying. As Ligo and other gravitational wave experiments around the world ramp up their abilities, who knows what wonders they will soon hear?
Marcus Chown, formerly a radio astronomer at the California Institute of Technology, is author, most recently, of What a Wonderful World: Life, the Universe and Everything in a Nutshell (2014).
Black Hole Blues and Other Songs from Outer Space
By Janna Levin
The Bodley Head, 256pp, ?17.99 and ?14.99
ISBN 9781847921963 and 4193
Published 31 March 2016
The author
Janna?Levin, professor of physics and astronomy at Barnard College, Columbia University, “grew up in Chicago and ended up in New York when I was 17. I can attribute the absence of certain habits to growing up in big cities. For example, I don’t drive.”
She shares her New York home “with prodigious musicians and artists: my husband Warren Malone, my 12-year-old son Gibson, and my 9-year-old daughter Stella. The guys are always playing instruments, loudly, and the little girl is always building something. On a particularly hectic evening – I was ruining boiled water, Gibson was cranking up the amp to drown out his father who was belting out a different song in a different room – Stella said while sanding down some wooden dowels with a power tool, always calm, ‘We are an unusual family.’”
Was she a studious child? “These days, crazy New York parents are over-involved in their kids’ schoolwork, pushing their children to be high achievers, enrolling them in classes every day after school. My parents never did my homework, or even checked my work as far as I can remember. It’s hysterical to even imagine that they would.
“They didn’t get involved, thankfully, and never pressured me. But they did share their curiosities and intellectual interests. My father is always wondering, always asking questions and marveling about natural phenomena. My mother reads compulsively. She loves fiction. The shelves are stacked two or three layers deep. We often talk about novels. My mother taught me how read. I don’t mean that she taught me how to sound out vowels and consonants, although she may have. I mean, she taught me how to be a reader.”
Of her undergraduate days, Levin says, “I loved college. I went to Barnard in New York City. I loved the classes and I loved the city. I wasn’t exactly a diligent student, but I was great at taking tests. I regret that. I could scoop in a couple of days before an exam and cram in a semester’s worth of material. But then all of that knowledge would evaporate as quickly as it was consumed. Shame. I wish I had studied slowly and consistently. I had to relearn everything as a result of my bad habits. But I was having too much fun in New York.”
In 2003-04, Levin served as the first scientist-in-residence at the Ruskin School of Art at the University of Oxford.
Asked if the experience accorded with her expectations, she recalls, “Richard Wentworth was the Master of the Ruskin School at the time. We used to laugh about that a lot, calling him Master. Richard is a rare gem, a truly great artist and a valued friend. He made me laugh. He would confuse me, always speaking in idiosyncratic metaphors. He challenged my worldview, forced me to look at things I hadn’t noticed – a glove that someone dropped on the street and another passerby placed on the spear of a gate. Odd forms of visual communication between strangers.”
She adds: “I loved being a scientist in residence and to some extent I’ve always been the scientist among artists. I lived in an artists’ warehouse in London while I was a postdoctoral fellow in the department of mathematics and theoretical physics at the University of Cambridge. In New York, although mostly I’m a professor of physics and astronomy, I maintained a studio in an artists’ collective where I wrote this book amid the mayhem. Even now I’m director of sciences at Pioneer Works, a center for art and science in Brooklyn. Pioneer Works is a magical place full of artists and writers – a truly vibrant community, like in my fantasy of Warhol’s Factory – only different, maybe better: innocent but provocative, not jaded.”
A Madman Dreams of Turing Machines, Levin’s 2006 novel about Kurt G?del and Alan Turing, won the PEN/Bingham Fellowship for Writers and the Mary Shelley Award for Outstanding Fictional Work. Was she tempted to write about these two figures in a work of biography or popular science, rather than fiction?
“At first, I tried to write Madman as nonfiction. I wrote a whole book, over 100,000 words, in an expository non-fictional approach. The draft just wasn’t compelling or exciting so I threw the manuscript away. I think I had to go through that process to internalise the theorems and a feeling for the characters. Then I plucked a few of their biographical facts and expanded a fictional scene for each line.
“I thought of the book as I would a film, in terms of these scenes. I tried to structure the narrative on G?del’s theorem, which says that there are true mathematical facts that cannot be proven from a logical sequence of steps. Some truths just don’t emerge from a collection of biographical facts. Yet still we can intuit a sense of these people, their lives, and their impact through fiction, maybe more faithfully than we could through plain biography.”
Asked if she has a favourite work of fiction about scientists or the process of scientific discovery, or about your discipline, Levin replies: “I love fiction. I get entranced with beautiful writing and I’m open to varied styles. I suppose I do lean towards conceptually intriguing themes. I don’t even know where to start: Cormac McCarthy’s The Road, Kazuo Ishiguro’s Never Let Me Go, Don DeLillo’s White Noise, Caryl Churchill’s play A Number. I love David Foster Wallace’s essays and novels by both Amises, Kingsley and Martin. Toni Morrison’s Beloved was the first masterpiece I remember reading. Philip Roth’s A Human Stain is unforgettable.”
In Black Hole Blues, Levin tells the story of some of the fascinating key figures in the Ligo project. Did she find it a challenge to do so when some of it is tragic, and all three of the troika are such complex people?
“I set out to write a very different book. I thought I’d write a straightforward science book about black holes using Ligo only as a hook for recent ideas. I ended up tripping down a very different road.
“I started to follow Ligo more closely, as a theorist looking in with admiration for the physicality of the experiment. I heard about all of this strife and tragedy and I wanted no part of it. So originally I buried all of these stories under the science. My editor Dan Frank said, ‘What are you doing burying this stuff? It’s incredible.’
“Some of these scientists are my close friends. I didn’t want to write about them and their conflicts. The very thought filled with me dread. But in the end, I knew that the better book followed the Ligo climb and that I had to shed the extra weight. You know the Twain quote, something to the effect, ‘I didn’t have time to write you a short letter, so I wrote a long one instead.’ I decided to spend the extra year and a half (two years?) writing a much shorter book.
What does Levin most hope we will have learned, in the field of astronomy, by the time she has retired?
“Scientists don’t retire. Rai Weiss dreamed up these machines as a young man in the late 1960s. He’s now in his early eighties. I’ve gone to the Ligo sites with him. He walks the 4km beam tubes sweeping away wasps, performing experiments on vibrational modes. People are always saying, ‘We better ask Rai.’ Even now, he’s still working on the next phase, always looking to the future. What do we all hope for? Something in the darkness that is completely unexpected. Something we never even imagined.”
What gives her hope?
“On the day of the announcement, I was interviewed about the gravitational-wave discovery for Al Jazeera TV,” Levin recalls. “Sandwiched between reports of violence in Iraq and terrorist attacks, the world seemed to take a breath to marvel at the universe. The last question they were going to ask me was along the lines, ‘What does this discovery mean for humanity?’ I wanted to say, ‘Science belongs to all of us, unites all of us. We’re all under the same sky.’ But we were interrupted by breaking news from the war in Syria.”
Karen Shook
后记
Print headline: Hark! A celestial symphony
