A bold revision of one of the most successful theories of all time: Einstein’s general theory of relativity. Physicists have long known that something is wrong with gravity. Einstein’s relativity and the theory of quantum mechanics are fundamentally incompatible, which has prompted the last 30 years of work in string theory and quantum gravity. However, John Moffat has identified a bigger problem: not only does Einstein’s theory not work in the world of the very small; it does not seem to work in the world of the very large either. Moffat has developed a modified theory of gravity, or MOG, that can explain the behaviour of our universe as well as Einstein’s, without resorting to dubious, yet long-claimed excuse for the existence of invisible “dark matter.” As John Barrow of the University of Cambridge asserts, the simplicity of Moffat’s model demands that physicists take this daring new theory seriously. Now, for the first time, Reinventing Gravity introduces general readers to Moffat’s groundbreaking new ideas about the universe.

A physicist presents a bold revision of Einstein’s Theory of Relativity that could represent “a paradigm shift not seen since Newton” (Publishers Weekly). Since the 1930s, physicists have noticed an alarming discrepancy between the universe as we see it and the universe that Einstein’s theory of relativity predicts. Galaxies spin so fast that, based on the amount of visible matter in them, they ought to be flung to pieces, the same way a spinning yo-yo can break its string. Cosmologists tried to solve the problem by positing dark matter—a mysterious, invisible substance that surrounds galaxies, holding the visible matter in place. Particle physicists, attempting to identify the nature of the stuff, have undertaken a slew of experiments to detect it. So far, none have. Now, John W. Moffat, a physicist at the Perimeter Institute for Theoretical Physics in Waterloo, Canada, offers a different solution to the problem. The capstone to a storybook career—one that began with a correspondence with Einstein and a conversation with Niels Bohr—Moffat’s modified gravity theory, or MOG, can model the movements of the universe without recourse to dark matter. Beyond that, his work challenging the constancy of the speed of light raises a stark challenge to the usual models of the first half-million years of the universe’s existence. Presenting the entirety of Moffat’s hypothesis to a general readership for the first time, Reinventing Gravity promises to overturn everything we thought we knew about the origins and evolution of the universe.