Einstein's Unfinished Symphony: Listening to the Sounds of Space-Time

Einstein is hot this year; not only has his brain traveled cross-country but his personal and scientific lives are being explored in depth. Gravity waves aren't as well known as the more familiar theory of E=mc2 (which is getting its own book this season, see Forecasts, Sept. 18), but cross-promotion of related titles will boost sales of this graceful little book about the mysterious subject. Those waves are the only form of radiation predicted by Einstein's theory of relativity that remain undetected (a gravity wave is created by the movement of an object; it is not the same as gravitational attraction). Unlike a wave of light, which moves through a medium, space-time, a gravity wave is similar to a wave in water, which is movement of the medium; however, a wave on a pond will go around you as you sit in a fishing boat, whereas a gravity wave will go through an astronaut in a spaceship as easily as it will pass through a star. Scientists predict the only gravity waves we will be able to detect at first are those from such galaxy-shaking events as supernova explosions or the collisions of binary neutron stars, but once gravity waves are graphed and analyzed, we should be able to confirm the existence of black holes, explore time back to the threshold of the big bang, and accurately map the dimensions of the universe. Today kilometers-long interferometer detectors are going online in Washington and Louisiana to detect gravity waves. Tomorrow scientists hope to have a space-based observatory tagging along behind Earth as it orbits the sun. Bartusiak (Thursday's Universe) has been writing about gravity waves for more than a decade, and her familiarity with the search and the scientists involved results in a thorough, engrossing and valuable chronicle.