Daniel Kennefick's "No Shadow of a Doubt"

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.

Kennefick applied the “Page 99 Test” to his new book, No Shadow of a Doubt: The 1919 Eclipse That Confirmed Einstein's Theory of Relativity, and reported the following:

The page 99 test works well on my book. It contains the book’s central argument, a subtle one which could easily be overlooked amidst the excitement and adventure of eclipse expeditions mounted to tropical locales by two English expeditions trying to test Albert Einstein’s then new theory of General Relativity. The test involved Einstein’s prediction that light is deflected from its path by the gravitational field of the Sun. The expeditions succeeded in overthrowing Newton’s theory and establishing Einstein’s theory on the world’s scientific stage. But the expeditions’ best known protagonist, Arthur Stanley Eddington, has been repeatedly accused of bias in favoring Einstein’s theory even before he set out to test it. But few experts ask, why would Eddington have been biased against such a well-established theory as Newton’s? The answer, I believe, is that Newton’s theory had been rendered inconsistent with the new world of relativity physics which emerged in the early 20th century, chiefly through the work of Einstein. Indeed, even while preparing for the eclipse, Eddington would have been uncomfortably aware that it was not cut and dried to state what the prediction of Newton’s theory actually was. In the end he took an earlier prediction of Einstein’s, made before the development of the complete theory of General Relativity, and labelled it the “Newtonian” result. Ironically he has been criticized for this too, when I argue that he was giving his old Cambridge college-mate Newton his best possible shot at redemption. But I think he must have been relieved that the experimental verdict went in favor of Einstein’s more precise new theory, which permitted calculations of this type to be done much less ambiguously.

Learn more about No Shadow of a Doubt at the Princeton University Press website.

My Book, The Movie: No Shadow of a Doubt.

--Marshal Zeringue