"Although Albert Einstein predicted the existence of black holes in 1916, they remained the stuff of science fiction until astronomers definitively proved his theory in 1971. Today, although we know more about black holes, we are far from a perfect understanding of these astronomical objects. This volume utilizes engaging fact boxes and vivid full-color photographs to help young readers better understand what we know about black holes as well as what questions remain to be answered. A list of relevant books and websites also provides a jumping-off point for future independent research." -- Provided by publisher.