Are we alone in the Universe? Was there anything before the Big Bang? Are there other universes? What makes stars shine? Where does Earth's water come from? Why is the night sky dark? Was there ever life on Mars? How do telescopes work? This engaging guide book answers all these questions and hundreds more, making it a practical reference for anyone who has ever wondered what is out in the cosmos, where it all comes from, and how it all works. Richly illustrated in color throughout, it gives simple yet rigorous explanations in non-technical language, summarizing current astronomical knowledge, without overlooking the important underlying scientific principles. This second edition includes substantial new material throughout, including the latest findings from the New Horizons, Rosetta, and Dawn space missions, and images from professional telescopes such as the Hubble Space Telescope and the Atacama Large Millimeter Array.