How old is Earth?
Why do its continents move around?
How does Earth's atmosphere help living things?
The books in the Astronaut Travel Guides take you on a virtual journey through our solar system and beyond. Discover the facts about your destination as well as information on what you need to take with you and who you might choose to come along. You can even read exclusive interviews with a real astronaut and astronomer to learn tips for studying and living in space!