"How did the universe form? What's the relationship between time and space? What scientific principles and natural forces rule our universe and how do we know about them? Answer these and many more questions in this . . . guide to our universe! In-depth text, . . . facts, and full-color photographs will guide readers through an exploration that mingles history, science, biographies, and more to examine the universe--and ponder the mysteries we're still learning about today"--Provided by publisher.