Here is a version of a review I wrote for the Wall Street Journal, before they edited it for house style and length.
Black Hole Blues
Knopf, pp265, $26.95
In February this year scientists announced the detection of a burst of gravitational waves from space. The waves, predicted by Einstein’s general theory of relativity, came from a pair of colliding black holes, each with about 30 times the mass of our Sun, in a galaxy more than a billion light years away. The ripple they produced jiggled the Earth by much less than the diameter of an atom. The astonishing story of how science was able to measure such a tiny effect, at a cost of a few hundred million dollars (which seems modest given the achievement) is told by Janna Levin in this superb new book. Levin is able to tell the tale so soon, and so well, because she has had privileged access to the experiment (known as LIGO, from Laser Interferometer Gravitational-wave Observatory) and the experimenters for several years, and knew that the first runs were due in September 2015. Like the experimenters, and everyone in the scientific community, she was stunned by the speed with which LIGO has produced results, but was able to squeeze in a brief mention of the news in an Epilogue.
Levin is herself a scientist, which explains her privileged access; but more than that she is a writer—a writer with a background in science, rather than a scientist who writes. Her book is less about the nuts and bolts of the science and technology, although it contains enough of that to satisfy our interest in how such measurements can be made, and more about the people, personalities and politics involved in getting such an expensive and long-gestating (four decades and counting) project to fruition. She gives due credit to Joseph Weber, a lone pioneer who built a gravitational wave detector in the sixties and thought he had found something, but was later proved wrong. In spite of this false start, Weber’s example encouraged interest in the possibility of detecting such waves, and stimulated others to take up the challenge. It was Weber who “brought Einstein into the lab.”
The contributions and clashes of the three key players in Levin’s story who did take up that challenge are each given comfortable space, and they should soon be sharing a Nobel Prize. They are Rainer Weiss, Kip Thorne and Ronald Drever, the “troika” who got things moving, both scientifically and politically.
The project grew out of a course on relativity theory that Weiss was teaching at MIT, in the early 1970s. His class were intrigued by the idea of gravitational waves – ripples in space – and to entertain them he devised a purely hypothetical idea (a “thought experiment”) for detecting such waves. The idea involved bouncing beams of light of mirrors to create so-called interference patterns. The passage of a gravitational wave through the experiment would change the interference pattern. Then, Weiss decided to try to turn the thought experiment into reality. He was, he said, “going to try to do the most interesting thing I could think of” even though the project, if it succeeded at all, would take decades. It looked as if the effort would fail for lack of funds. But in 1975 Weiss met Thorne, a leading theorist in the field of relativity, and also a leading light at Caltech, who was seeking a partner to work on the search for gravitational waves. It was a marriage made in heaven. The troika was completed when they headhunted Drever from Glasgow, where he had established a formidable reputation as a hands on physicist who got things done, and was working on his own gravitational wave detector. Drever had been brought up in the sealing wax and string tradition of British scientists such as Ernest Rutherford, and was a genius at cutting corners and making things work – provided he was left to do it his way. This was an asset when the project was young and impoverished, but as Levin details his approach became a problem when the project became a large, well-funded bureaucratic organisation with no room for mavericks.
But the Nobel Committee had better get its skates on; none of these pioneers is in the first flush of youth, and Drever, sadly, now suffers from dementia. Not that Nobel Prizes, and the lust for them, are necessarily always a good thing. In an interview with Levin, Weiss refers to them as “the sin in this field”, causing friends to fall out with each other over claims for priority.
On the scientific side, I was pleased to see Levin giving due emphasis to the importance of the discovery of a system known as the “binary pulsar”, which was seen in the early 1990s to be losing energy in a way which could only be explained by gravitational radiation. This was itself Nobel-winning work, and gave a great boost to the attempt to detect gravitational waves directly. Indeed, it was the binary pulsar that “proved Einstein right”, in so far as that needed proving. The importance of LIGO is that it provides a way to study gravitational waves directly, opening a new window on the Universe, potentially as important as opening up radio or X-ray astronomy. So far, it has detected what people expected it to detect; the real excitement begins when it begins to detect the unexpected.
There are some minor irritations regarding Levin’s style. She is clearly unfamiliar with English places and titles, which won’t bother many of her readers. More annoyingly, when introducing the physicist John Wheeler she cannot resist a parenthetical “difficult not to mention his most famous student, Richard Feynman”. Actually, it is easy. Just leave out that sentence. But this is a small price to pay for the pleasure of Levin’s easy style, which makes the reader feel like they are sitting in on her interviews or watching over her shoulder as she writes.
I am much more uncomfortable about Levin’s telling, in my view too detailed, of the rivalries which led Drever to be pushed out of the project at the end of the 1990s. The other protagonists were interviewed and gave their versions of the truth in detail, but Drever is now unable to tell his side of the story. I am not sure that we need all the details anyway, but in the circumstances I definitely concur with the comment made to Levin by Weiss: “Nobody wants to resurrect this stuff. It’s unfortunately in the public record now. But it doesn’t have to be in your book.” Indeed not.
But I don’t want to end on a sour note. This is a splendid book that I recommend to anyone with an interest in how science works, and in the power of human imagination and ability. What LIGO actually measured on 14 September 2015 was a change in the length of detector arms 4 kilometres long that amounted to one ten-thousandth of the width of a proton. To scale that up to “see” a change in length as great as the width of a human hair would require a detector as long as a hundred billion times the circumference of the Earth. It is worth sitting back and letting that sink in. If human beings are capable of measuring that, they are capable of almost anything, given the will to do it. And if you want to know how they did it, in spite of all the trials and tribulations, you will have to read the book.
John Gribbin is a Visiting Fellow in Astronomy at the University of Sussex, and author of 13.8: The Quest to Find the True Age of the Universe.