Book excerpt: Is there life outside the Earth? What is a black hole? What was the weight of the Apollo spacecraft? This compact guide presents essential facts about the solar system, galaxies in deep space, manned space flights, space stations and probes, and much more. Each title in Barron’s Pocket Factbooks seroes focuses on one of the natural or social sciences. It presents fascinating, sometimes little-known facts about its subject, as well as answers to frequently-asked questions. These books make handy reference sources for students, freelance writers, and general readers who are interested in finding out the how, where, when, and why—the specific facts and details relating to science, technology, natural history, and social history. All titles in this series are filled with attractive color photos and illustrations.