Explore the dark side of space in Out of this World, a new and exciting series for struggling readers. Is time travel possible? How do black holes theoretically support time travel? These and other fascinating questions are discussed in the Theory of Time Travel title using considerate text that is written at a higher maturity level with a lower reading level to engage struggling readers. A table of contents, glossary with simplified pronunciations, and index all enhance reading comprehension. Sidebars include hands-on experiments, spotlight biographies on women in science, tech connections, and far out facts.