Black Hole Blues and Other Songs From Outer Space

Book Review: Black Hole Blues and Other Songs from Outer Space by Janna Levin

Last February the Laser Interferometer Gravitational-wave Observatory (LIGO) made a historic announcement: they had detected gravitational waves, ripples in the fabric of spacetime which were theorized by Albert Einstein a century ago. LIGO's immense discovery, but moreover the immensity of the LIGO project itself, are the subject of Black Hole Blues and Other Songs from Outer Space, the latest book from renowned cosmologist Janna Levin. The author of two other mainstream scientific books — How the Universe Got Its Spots and A Madman Dreams of Turing Machines — Levin appears to be the ideal person to relay this incredible story of achievement. Black Hole Blues has so much going for it: a topical and meaningful discovery at its core, an expert on the subject matter as its author, and an extremely catchy title. You can therefore imagine how disappointing it is to read this book and discover how little it delivers on its promise.

With a scientist at the helm, I expected Levin's account to center on, well, the extremely complex and fascinating science behind LIGO. But let's back up a moment. What is LIGO?

LIGO is the culmination of more than 40 years of active experimentation and 100 years of theory. It is an NSF-backed multi-hundred-million-dollar wager on one of Einstein's most controversial theories, one that even he had trouble coming to grips with. More concretely, it is a pair of nearly identical observation sites tasked with detecting brief, minuscule changes in distance — in particular, when a 4km-long tube grows or shrinks by less than the width of a proton for a fraction of a second. Such an occurrence would (and did) confirm Einstein's theory of gravitational waves, the idea that when some astronomically powerful event transpires —like two black holes smashing into each other or a neutron star exploding — the very spacetime around that event will ripple. LIGO represents an audacious group of scientists not only agreeing with Einstein's theory but brazenly suggesting that we could actually detect those waves on Earth by building the most powerful microphone ever, a microphone that listens by shooting a laser into million-dollar mirrors that hang from a single thread of glass.

See how easy it is to get wrapped up in the science? The stuff is utterly ludicrous, on a plane with the Improbability Drive in The Hitchhiker's Guide to the Galaxy. Disappointingly for the nerd in all of us, the science behind LIGO is decidedly not the focal point of this book. Instead, Levin aspires to expose the personalities and personal struggles behind LIGO. Her undertaking is therefore largely journalistic. With access to hours of recorded interviews beginning in the 1970s, when the idea of LIGO began to take shape, and some of the lead physicists themselves, Levin has ample resources to tell the story as it unfolded.

Despite these advantages, Black Hole Blues is hampered in two significant ways. The first is that, if Levin's account can be trusted, LIGO's history is not nearly as interesting as its science. It can be broadly summarized as follows: scientists once skeptical about Einstein's gravitational-wave theory eventually came to believe it, and — after acquiring funding and building complicated instruments — confirm it. Their achievements are tremendous but the personal intrigue behind them is limited. With some of the world's most high-profile academics teaming up across organizational and international lines, fireworks are to be expected. Yet there are surprisingly few outbursts. The scientists seem downright mild according to the interviews that Levin references, which are dulled by memory and self-censorship. There aren't any pivotal, exasperated "It just won't work!" moments. One scientist — Joseph Weber — does become discredited by his poor experimentation techniques and questionable observations, but this affair merely leads to his getting kicked off the project. It doesn't even drop him from the good graces of his peers. With so much at stake both scientifically and professionally, it's a wonder that Levin isn't able to cull more excitement from LIGO's story.

This brings us to the second issue: Levin's narrative shortcomings. Structurally, she's a bit all over the place. It's not uncommon for her to dedicate a few pages to a 1970s interview, then switch to a present tense interview with someone else, then drop that topic altogether and marvel at the scale of one the observatories — all within the same chapter. This fluidity, a stratagem assumedly deployed to prevent us readers from becoming bored, can have the inverse effect of leaving us dizzy.

This is not the only stylistic hiccup. Levin adores analogies, and why shouldn't she? They're a scientist's best hope of helping us laymen understand her complex area of expertise. Sometimes they're well executed, like this one which describes how gravitational waves are detected and then converted to audio:

In a less than perfect analogy, astrophysical calamities are the finger pickers, spacetime is the set of strings, and experimental apparatus is like the body of the guitar. Or, moving up a few dimensions, astrophysical calamities are the mallets, spacetime is the skin of a three-dimensional drum, and the apparatus records the modulations in the shape of the drum to play the silent score back to us as sound.

The purpose of this metaphor is clear: to help us understand an invisible and complex concept. In other places, though, Levin loses sight of the purpose of her literary devices and unnecessarily attempts to evoke the poetic. At one point she compares a LIGO observatory to a hospital patient: the blood is the light from the laser, which happens to be red; the arteries are the tunnels that house the laser; the doctors are the researchers; the life-support is the electricity, or maybe the NSF. Yeesh. Even Levin knows it's a stretch: "I'm not inclined to press the analogy of the doctor and the patient; it doesn't really hold all that very well." Then why bother?

You can forgive a scientist for employing a few clumsy similes, but the larger issue is not one of narration but journalism. Levin proves overeager and undisciplined with her selection of details. She fills a surprising proportion of Black Hole Blues' 257 pages with tidbits that are neither here nor there. One chapter begins with a playful but long-winded summary of Stephen Hawking's penchant for making poor scientific bets. This sets up an anecdote in which Hawking loses a wager to Kip Thorne, one of the lead scientists on LIGO:

When he did pay up in the form of the agreed-upon subscription to a sexy magazine it was "to the outrage of Kip's liberated wife." At least that's the story propagated since. "I was never outraged," says Carolee Joyce Winstein, Kip's liberated wife. "My reaction was one of surprise more than anything . . . because I thought the women's movement was well under way in sensitizing folks about these things. Clearly I was mistaken. This was likely too heavy for the press and so it got reduced to the stereotypic 'wife was outraged' story." Carolee, who is not at all prudish, finds the whole thing rather amusing.

If Levin's wager is that we, too, will find this whole thing rather amusing then she's a worse gambler than Hawking. This is one of a number of instances in which Levin drops in a long quote rather than delivering the punchline herself. The result is a book that feels complete and accurate but that tends to wander, leaving the reader wondering, "Why go there?"

Indeed this is my biggest question for Levin, not because her storytelling is particularly weak but because her scientific explanations are particularly strong. It should come as no surprise that her best writing comes in the form of rendering complex science comprehensible, like in this instance where she's explaining the idea underlying LIGO:

The idea: Suspend mirrors so they're free to rock parallel to the earth and watch them toss on the passing gravitational wave. Keep track of the distance between them, and their motions will record the changing shape of spacetime. Since light's speed is a constant, the time it takes for light to race the track measures the length of the course. If the light travel time is a little longer, the distance between the mirrors has stretched. If the light travel time is a little shorter, the distance between the mirrors has squeezed.

Straightforward but illuminating paragraphs like these are rare. Levin frequently gets caught up in trying to be clever — as in the doctor-patient analogy mentioned earlier —instead of trying to be readable. At one point she indulges us with an interesting discussion of LIGO's experimental design but it lasts less than two pages. Too many questions go unanswered. How is light interference measured? How will the construction of more observatories increase what we learn from gravitational waves? How can researchers isolate the signal from noise when the noise is louder than the signal?

This last question is one of extreme importance for LIGO, and Levin, to her credit, does touch on it from time to time. "Noise is a big topic," she explains. "There are people in the collaboration who work just on noise." When a burrowing groundhog or a passing garbage truck can upset an entire observatory, it takes an army of researchers to "[push] the floor of the noise down, giving a chance for a real signal to compete with the background racket." With Black Hole Blues, Levin steps into a similar role not just as the liaison for a rapidly expanding field but as its amplifier. Unfortunately for her readers, the output is mostly noise.

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Source: https://dsfish.medium.com/book-review-black-hole-blues-and-other-songs-from-outer-space-by-janna-levin-11115c601250