By Jay M. Pasachoff
Imagine being alive in the time of Galileo, when he first turned his telescope on the heavens and discovered seas on the Moon, moons orbiting Jupiter, and more. (Less known: Simon Marius was only one night behind Galileo in noting the moons.) Well, we live in such a time, since this year we learned of the discovery of gravitational waves, opening a whole different way of studying the Universe besides the more traditional light and its variations (such as x-rays or radio waves).
Janna Levin (ΦBK, Barnard College, 1988), a physics and astronomy professor at Barnard College, attached herself for years to the group of people who discovered the gravitational waves. The group is about a thousand people strong (800 of whom are listed at the end), and the scientific papers in the Physical Review and the Astrophysical Journal had 1008 coauthors. We learn about the personalities especially of the three people most responsible for the project and its ultimate success: the Caltech theoretician Kip Thorne, the MIT experimentalist Rai Weiss, and the Caltech iconoclastic experimentalist Ron Drever. In fact, much of the book is an exposé of the quirks of these individuals and the interactions between them and others in the consortium.
The consortium is LIGO, which stands for the Laser Interferometer Gravitational-Wave Observatory, and even the word Observatory is controversial since it is an astronomical term for observing things and LIGO was paid for by the US National Science Foundation’s Physics Division, and for decades didn’t see anything. (In preparing a physics-for-poets text of mine published in 1980, I visited Weiss at MIT to see the apparatus in its then state, and wrote correctly that “the researchers hope that future larger versions of this laser interferometer would be sensitive enough….”) But on September 14, 2015, it detected a chirp of signal that validated all the years of work.
Already Thorne, Weiss, and Drever have been collecting prizes, such as the Shaw Prize, the Kavli Prize, the Gruber Prize, and the Breakthrough Prize in Fundamental Physics (2/3 of whose $3 million was divided among 1012 LIGO collaborators) this year, and are favored to win this fall’s Nobel Prize in Physics. But there are some precursor pretenders, and we will see in October if the Nobel Committee in Stockholm tries to distribute the prize internationally. Levin’s book shows us why Thorne, Weiss, and Drever deserve all the prizes, but also casts a wider net.
Interspersed in the book are pages-long asides that explain black holes, pulsars, and other astronomical matters useful for understanding what goes on in the Universe. Levin’s writing is literary in tone, and she casts many a pretty phrase, making the book readable for the general public. She understands the physics and has spent years interacting with the principals, as well as benefiting from interviews from the Caltech Archives conducted by Shirley Cohen.
But I disagree with the publisher’s decision (at least, probably theirs) to continue the book as originally written when the discovery from last September was secretly told her, still months before it was made public. The actual discovery—the report of which brought tears to my eyes—appears only in an Epilogue. I think even at a late stage of publication, this most dramatic discovery in the Universe in 400 years should have held up publication until the news was put first, in a prologue, and a few tenses changed throughout.
For those of us who know so many of the principals, it is fascinating to read about their personal interactions with others, often unfavorably. For those who like to know how the hot dog is made within its casing, this book gives sociology of science. A lot of dirt is presented to us, in which some people will be interested while others might prefer more straightforward science.
In one way, Levin (or Knopf) fails the test of reliability: not knowing the difference between a scientist being at Princeton University or at the Institute for Advanced Study, which is in Princeton, New Jersey (and where Einstein spent his last decades), or that the famous 200″ telescope is at the Palomar Observatory on Palomar Mountain (there is no such place as “Mount Palomar”), or exactly what “maser” stands for. Such seemingly minor errors makes one wonder about the reliability of other details in the story.
Ultimately, LIGO detected a minuscule difference in the 4-km length of an arm perpendicular to another arm in both its Hanford, Washington, and its Livingston, Louisiana, sites. The difference is much less than atomic diameter compared with that 4-km length, but the technique of interferometry can pick it up—as long as the details of the experiment can account for seismic causes on Earth, including not only earthquakes but also traffic on roads and even the felling of trees nearby. The triumph of September 14, 2015, announced after much checking in February 2016, showed that two giant black holes, 29 and 36 times the Earth’s mass, respectively, spiraled into each other and amalgamated into a single, even-more-massive black hole, with about two solar masses of material converted into the gravitational waves that we received that, when converted into sound, sounded like a chirp—a subsecond interval of increasing frequency.
A second major black-hole collision was reported to the American Astronomical Society in June 2016, and gravitational-wave astronomy is now on what we hope is a steady course of continued greatness. Janna Levin’s book gives insights into just how hard it was to reach this point.
Astronomer and author Jay M. Pasachoff is the director of Hopkins Observatory and Field Memorial Professor of Astronomy at Williams College. He is a Visitor in the Planetary Sciences Department of Caltech. Williams College is home to the Gamma of Massachusetts Chapter of Phi Beta Kappa.