Review: Black Hole Bluesby Jeff Foust
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| The book is less about the science of gravitational waves than the very human quest to discover them. |
That feeling creeps into the minds of readers in the opening pages of Black Hole Blues and Other Songs from Outer Space, Janna Levin’s history of the study of gravitational waves, with a particular focus on the development of the Laser Interferometer Gravitational-wave Observatory, or LIGO. “As the global network of gravity observatories near the final stretch of this race,” she writes in the book’s opening pages, referring to the decades-long efforts to detect gravitational waves, “it gets harder to turn attention away from the promise of discovery, although there are still those who vehemently doubt the prospects for success.”
In retrospect, those words were clearly written before February, when LIGO scientists announced they had detected gravitational waves for the first time, a detection last September at the two LIGO facilities in Louisiana and Washington state (see “A thump in the night”, The Space Review, February 15, 2016). Rest assured, though, that this discovery has not made the book obsolete; in fact, it may have made it even more relevant than before.
The book is less about the science of gravitational waves—although Levin, a physics professor at Columbia University’s Barnard College, clearly describes enough of the science to make their importance clear to the reader—than the very human quest to discover them, and thus offer another confirmation of Einstein’s theory of general relativity. And that quest was fraught with challenges that had little to do with the technical challenges of detecting minute ripples in spacetime.
At one time, decades ago, scientists thought they had discovered gravitational waves. In 1969, Joe Weber, a physics professor at the University of Maryland, reported detections of gravitational waves using large aluminum bars instrumented with quartz crystals to detect when the bar was stretched or squeezed by those waves. That discovery shocked the physics community, but that surprise turned to dismay within a few years after other scientists failed to replicate his results. Weber, who insisted his results were valid, was effectively ostracized from the field.
It was in that environment, with ongoing debate about whether gravitational waves could be detected, or even existed, that a few scientists started to examine other ways to find them. At Caltech, theoretical physicist Kip Thorne was looking for ways to detect gravitational waves. At MIT, physicist Rainier Weiss stumbled upon the idea of using a laser interferometer to detect spacetime ripples while teaching a course on general relativity. At the University of Glasgow, Ron Drever was also working on interferometers cobbled together from whatever spare parts he could get his hands on. Eventually the three would come to work together to develop far larger interferometers—too big to fit in a physics lab—needed to detect gravitational waves.
This “troika,” as the trio of Drever, Thorne, and Weiss came to be known by, was not a congenial collective. The three were brilliant in their own ways, but in very different ways that did not lend themselves to either harmonious collaboration or effective project management. Just as the collision of supermassive black holes generates the gravitational waves they sought to detect, the collision of their similarly-sized egos generated ripples that imperiled their efforts to win funding from the NSF to develop what would become LIGO.
Levin turns this tortured early history into a compelling read, even if the outcome—LIGO, after all, does get built—is already known. Drever is ultimately pushed out of the project, and a former Caltech provost, brought in to run the project and secure funding, is also later let go. The project eventually completes construction of LIGO in 2000, but the original instruments fail to detect gravitational waves, something foreseen back in the project’s early days, which expected a second, more advanced generation of instruments would be needed. That was right: the gravitational wave detected last September was during the early science phases of what’s known as Advanced LIGO.
| Levin turns this tortured early history into a compelling read, even if the outcome—LIGO, after all, does get built—is already known. |
Levin also takes the reader behind the scenes of the two LIGO facilities, which, while functionally identical, do have differences because of their different locations: the one in Washington state is on isolated federal land used decades ago to produce plutonium, while the Louisiana one is on swampy land where the challenges include alligators and hunters. Oddly, the book includes no photos of either side to better illustrate either the LIGO sites or the people who made it possible.
However, the book does illustrate in words those involved with LIGO, particularly the troika. Thorne and Weiss sat down for extensive interviews with Levin, and contributed complimentary blurbs about the book on the back cover. (Drever, now living back in Scotland and suffering from dementia, was not interviewed, but Levin was able to use earlier interviews from a Caltech oral history project.) It results in fascinating insights, although sometimes Levin’s prose becomes a bit florid. Early in the book, she describes Weiss’ transition to a professor emeritus to devote more time to LIGO by saying he “molted the venerable role of professor of physics,” part of a passage that seemed unnecessarily convoluted and made Weiss sound a bit, well, reptilian.
Even without any news about LIGO’s gravitational wave discovery, Black Hole Blues and Other Songs from Outer Space would have still been a fascinating book about not just the science of gravitational waves but also the very human process by which that science gets done. Fortunately, Levin was able to include an epilogue about the discovery, thanks to a confidential email she received in December, two months before the discovery was publicly announced and published in a journal, which was weeks before the publication of the book. That discovery itself, and its scientific implications, may one day be the subject of its own book, but this book’s history of the efforts leading up to that discovery are likely to stand the test of time.