Magnificent Universe Ibs583618

With an impressive constellation of pictures (including computer-enhanced images from the Hubble Space Telescope), Croswell (Alchemy of the Heavens) takes readers on an introductory tour of the celestial spaces and places that interest astronomers, from earth and its neighboring planets, to nearby stars and the interstellar medium, to the limits of the observable universe (which turn out to be 15 billion light-years from earth). Croswell's summaries of astronomical and cosmological knowledge make clear if very compact introductions to these subjects, fit to accompany the magnificent images, and divide into four segments: ""The Planets,"" ""The Stars,"" ""The Galaxies"" and ""The Universe."" Potent photographs alternate with memorable facts: explaining that sunspots arise from magnetic fields on the sun, Croswell stops to note that, for much of the 17th century, there simply were no sunspots; as a result, the sun faded and the earth cooled. Near the end of his last chapter, Croswell tells us why the universe will probably go on expanding and cooling down forever: though there's plenty of ""dark"" (undetectable) matter between stars (dark matter's gravity holds galaxies together), there'd have to be five times as much as there probably is for expansion to someday halt. Over 100 spectacular photographs show, rather than tell, readers exactly why kids grow up to be astronomers. Some images come from NASA spacecraft, including Viking and Voyager. Appended tables supply vital statistics on, for example, the diminutive moons of Uranus, and the size and age of the best-known stars. (Oct.)