«Black hole blues», by Janna Levin
In the back room of space
In November 1916, Einstein published a paper predicting the existence of gravitational waves. In September 2015, the two detectors of the Laser Interferometer Gravitational-Waves Observatory (LIGO) project, located more than 3,000 km away from each other, made both the first detection of gravitational waves and the first direct observation of the collapse of two black holes into a single one. The story of LIGO is the subject of this book, whose title is already indicative of its tone.
Janna Levin is an American theoretical astrophysicist who combines her research with a fruitful outreach activity. She is the scientific director of the New York cultural centre Pioneer Works, a meeting place for artistic and scientific disciplines. She spent 2015 preparing and writing this book, and finished it just as gravitational waves were detected. The result gives a fairly detailed insight into the beginnings and operation of the major project that is LIGO. Each detector consists of two perpendicular four-kilometre-long tubes, inside which a beam of light makes multiple reflections. The observation of light interference makes it possible to detect tiny variations (of just one part in three billion!) in the length of the arms, produced by the arrival of a gravitational wave. Gravitational waves, black holes, and neutron stars are discussed in the book, along with the dreams of the project’s promoters, Rainer Weiss, Ronald Drever, and Kip Thorne to succeed where others had failed. Levin tells us about the obsessions of these scientists, their personal trajectories, their enthusiasm, doubts, and disappointments. She also tells us about other similar projects, such as the Italian Virgo project, with which coordination was necessary to compare results.
Levin interviewed the scientists behind the project, visited the facilities at the Hanford Site (Washington) and Livingston (Louisiana), followed their day-to-day activities, spoke to many of the project’s participants, shared discussions with the postdocs at Caltech…. She knew how to listen and ask the right questions, but also the most cheeky ones. In this way, she explains many important aspects that are often unknown outside the project itself – especially in a large project. The difficulties of the promoters within their institutions, the scepticism of many colleagues, the rivalries between scientists, the negotiations with the National Science Foundation to get the project approved and funded, the interventions in the US Senate to get the green light for an exceptional expenditure, the rivalry between states to host the project or the initial hostility of the Livingston facility’s neighbours.
This sociological aspect is the most original aspect of the book, in my opinion. Levin has been able to show all that lies behind a big science project and explain it in a very attractive way. The book will interest even those readers who are not attracted to gravitation.