The Irresistible Attraction of Gravity: A Journey to Discover Black Holes

Rezzolla (Relativistic Hydrodynamics), director of the Institute for Theoretical Physics in Frankfurt, Germany, serves up a difficult-to-follow primer on gravity and its role in general relativity. He describes how understandings of gravity have changed throughout history, from Galileo’s primitive physics to Einstein’s postulation that the presence of matter “curves” spacetime. Detailing some of the more eye-popping consequences of gravitational physics, Rezzolla explains how neutron stars form from massive stars collapsing under their own gravity and how gravitational waves “represent the propagation, at the speed of light, of ‘ripples’ in the spacetime curvature.” Elsewhere, Rezzolla recounts how his team created the first photograph of a black hole by mapping the radiation around the event horizon using a sophisticated technique in which two radio-telescopes thousands of miles apart act as a single telescope “with a diameter equal to the distance between the two.” Rezzolla’s expertise shines, but despite his intent to “steer us away from the treacherous waters of erudition and technicalities,” his discussions of Einstein’s theory of relativity and the advanced math necessary to observe black holes get bogged down in scientific jargon. This isn’t for the faint of heart, but science buffs interested in cutting-edge astronomy will be more than satisfied. Photos. (Mar.)