Gravitational Waves: Volume 1: Theory and Experiments

  • Michele Maggiore
Oxford University Press: 2007. 572 pp. $90 0198570740 9780198570745 | ISBN: 0-198-57074-0

Gravitational waves are ripples in space-time that travel through space at the speed of light. They are emitted by astrophysical sources such as binary stars or colliding black holes, or by violent phenomena such as cosmic strings or inflation in the very early Universe. Because they affect matter only weakly, gravitational waves are very hard to detect. To do so we need large instruments — interferometers several kilometres on a side — with extremely sensitive quantum-limited detectors, only recently available. The very fact that gravity couples so weakly to matter means that gravitational waves travel almost unimpeded through any material between us and the source of the gravitational waves. So they can provide a unique, direct view of some of the most dramatic cosmic events, including black-hole collisions or even the Big Bang itself.

At least that's the theory. Gravitational waves are confidently predicted on the basis of general relativity, but we've not been able to directly measure them so far. Their detection will be a scientific triumph, opening a brand new window onto the Universe. Over the past three decades, the technology of gravitational-wave detection has been steadily advancing, and sophisticated instruments are now operating in Italy, Japan, Germany and the United States. Versions coming online within a few years should reach the sensitivities required to see the gravitational waves expected from distant collisions involving black holes or neutron stars. Far more ambitious space-based experiments such as the Laser Interferometric Space Antenna (LISA) — a mission jointly led by the European Space Agency and NASA — are also planned for launch within the next decade. A growing community of experimentalists and theorists is forming, focused on the huge challenges of instrumental design and data analysis.

Students and experienced researchers will welcome Michele Maggiore's timely and authoritative new text book of classic results, detailed applications to specific gravitational wave sources, advanced mathematical methods and experimental issues. The first of two planned volumes, Gravitational Waves provides a thorough grounding in the theory of gravitational wave emission and a description of the practical techniques involved. It gathers many scattered results from a wide literature into a detailed, coherent, pedagogical review. The second volume, still in preparation, will cover the astrophysical and cosmological sources of gravitational waves, and what we can hope to learn about them.

The book is accessible to students who have taken a course in general relativity; it takes off from standard graduate-level textbooks, deriving the main results. In some places, though, the language is imprecise or lacks clarity; in others, too much space is devoted to the details of very specific applications. Also, an unfortunate number of minor grammatical errors and typos are scattered through the text. Hopefully, this will not distract readers from the large body of excellent and useful material that Maggiore has assembled on an important new frontier of astronomy and of fundamental physics. I look forward to Volume 2, and even more so to the dawn of gravitational-wave astronomy.