Traveling at the Speed of Thought: Einstein and the Quest for Gravitational Waves

by Daniel Kennefick

Since Einstein first described them nearly a century ago, gravitational waves have been the subject of more sustained controversy than perhaps any other phenomenon in physics. These as yet undetected fluctuations in the shape of space-time were first predicted by Einstein's general theory of relativity, but only now, at the dawn of the twenty-first century, are we on the brink of finally observing them.


Daniel Kennefick's landmark book takes readers through the theoretical controversies and thorny debates that raged around the subject of gravitational waves after the publication of Einstein's theory. The previously untold story of how we arrived at a settled theory of gravitational waves includes a stellar cast from the front ranks of twentieth-century physics, including Richard Feynman, Hermann Bondi, John Wheeler, Kip Thorne, and Einstein himself, who on two occasions avowed that gravitational waves do not exist, changing his mind both times.


The book derives its title from a famously skeptical comment made by Arthur Stanley Eddington in 1922--namely, that "gravitational waves propagate at the speed of thought." Kennefick uses the title metaphorically to contrast the individual brilliance of each of the physicists grappling with gravitational-wave theory against the frustratingly slow progression of the field as a whole.


Accessibly written and impeccably researched, this book sheds new light on the trials and conflicts that have led to the extraordinary position in which we find ourselves today--poised to bring the story of gravitational waves full circle by directly confirming their existence for the very first time.

Genres: Science, Physics

336 pages, Hardcover

First published March 26, 2007

About the author

Daniel Kennefick is associate professor of physics at the University of Arkansas, Fayetteville. He is the author of Traveling at the Speed of Thought: Einstein and the Quest for Gravitational Waves and a coauthor of An Einstein Encyclopedia (both Princeton).

Reviews

[Gabriel Macedo]

The (somewhat tedious) process of writing an introduction to a master's thesis stirred my curiosity regarding the history of gravitational-wave physics. Upon reading Kannefick's book I encountered a detailed, well-documented, and thought-provoking analysis of the development of this field. Since the first detection of gravitational waves by the LIGO/VIRGO collaboration took place eight years after the publication date, an expanded second edition doesn't seem like a bad idea.

[Chunyang Ding]

Honestly, this is a history of science textbook pretending to be a popsci book. While the subject matter is very interesting, the author takes a very academic approach to analyzing the different arguments and analogies for gravitational waves. It is also a bit sad that the book just misses the detection of gravitational waves by a few years.

The content is wonderful and excellently researched, and the author is at a very good place to tell the story. But the method of telling the story is as dry as can be.

[Nathan Lee]

This is a fascinating account about the history of gravitational waves in the physics community, which follows about ninety years of insight, research, discovery, and debate. It took almost a year for me to get through, but the progress was worth it. As a student of physics, I have wanted to learn about the study of gravity for some time and was excited when, funny enough, I saw the title of this book while sending out PhD applications. I was intrigued by the title and am happy to say that the book itself did not disappoint.

It is no small feet that Dr. Kennefick was able to form a narrative of the notable people and physics involved in studying gravitational waves, from Einstein to Wheeler and Thorn. He avoids bombarding the reader with figures and equations they may be unfamiliar with, but he explains enough of the physics to intrigue those who are, all while telling a compelling story that is some parts research, some parts mystery, and some parts personal experience. I also appreciate his sensitivity to the subtleties of scientific debate and the perennial tensions between creative intuition, methodical calculation, and fresh research.

The chapters do run long enough to where subheadings would be helpful, but the book rewards the reader who sticks through to the end. I had a hey day annotating the pages and noticing connections between theorists and their theories, and I felt as though I was along for the ride on this heartfelt trip through history. As a nice addition, Kennefick, who wrote the book in 2007, shares his optimism that gravity waves are on the verge of being detected. Only eight years later, they were detected for the first time by the LIGO observatory, the planning of which is actually mentioned in the book. Reading it now, one feels that they are part of the story the book tells.

I recommend this book to anyone who loves physics or is interested in the history and philosophy of science. I learned quite a lot from it, and I think it is one that I will often refer to.

[Friend of the Talking Bird]

Although the possibility that gravitation propagates with a finite speed was considered by Pierre-Simon Laplace, who realized that this would cause planetary orbits to decay, in the 18th century, modern study of gravitational waves began in 1916 with Albert Einstein's General Relativity. The equations of General Relativity are highly nonlinear, so all nontrivial solutions to them have to be approximate or numeric. In 1918 Einstein came up with an approximate formula relating the power of radiated gravitational waves to the third time derivative of the quadrupole moment of the source. Electromagnetic waves are radiated by dipoles, but, because of conservation of momentum, the gravitational dipole moment of a closed system is constant; only a quadrupole can radiate gravitational waves. During the next half century and more, physicists argued whether gravitational waves even exist, and if so, whether their radiated power is described by the quadrupole formula or something else. Only in the 1970s did astronomers discover a pair of neutron stars, one of which is a pulsar, orbiting each other, which lose energy to gravitational waves, which makes their orbit decay in exact agreement with Einstein's quadrupole formula. The formula has the fifth power of the speed of light in the denominator, which makes detection of gravitational waves very difficult.

This book was published 8 years before gravitational waves were actually detected using a laser interferometer, built using extreme engineering, which was almost 100 years before Einstein described them.

[James F]

A semi-popular history of the concept of gravitational waves from the origins of General Relativity through the various disputes to the observational confirmation by the discovery of binary pulsars, and the beginnings of the search to detect the waves themselves. (I finished the book last night; this afternoon, the BBC News had the report that they have just been detected for the first time.) I call the book semi-popular because, while aimed at a lay audience and without being highly mathematical, it does require for example knowing what tensors are and what invariance and covariance under transformations of coordinates mean and why this is important. In short, it isn't a book for absolute beginners. The author is particularly interested in using the history of general relativity and gravitational wave studies to present his meditations on the philosophy of science, which not everyone will be interested in (I was, as a former philosophy student). The book is occasionally repetitious, especially in discussing individual scientists and their personalities.

[Noah]

Gravity waves.

Higgs Field.

SEED review.