From our own solar system to the edges of the universe, 50 Astronomy Ideas You Really Need to Know is your introduction to the most important concepts, discoveries and mysteries in astronomy. How did the universe begin? How did our own sun and moon form? What happens at the fringes of our galaxy and in the heart of a black hole? Is there life elsewhere in the cosmos?In fifty fascinating essays covering the central ideas of astronomy and accompanied by diagrams, definitions of essential terms and timelines of key discoveries, this book examines the nature and variety of our universe - the life cycle of stars, the formation of planets, the structure of galaxies and the puzzles of dark matter and the quantum universe. Expansive and illuminating, 50 Astronomy Ideas You Really Need to Know contains everything you need to know about science's most awe-inspiring discoveries.