Astronomy is an ancient science on the cutting edge. Although it's been around for more than 5,500 years, astronomers say that we've learned more than 90 percent of what we know about the universe in just the last 50 years. Of this body of knowledge, a disproportionate amount has been acquired in the past decade, with each new year yielding more information than the last. The Complete Idiot's Guide to Astronomy, Second Edition, covers these new advances and discoveries and is repositioned to focus more on exciting, cutting-edge cosmology topics and less on backyard astronomy.