Gravity causes an apple to fall to the ground and keeps the moon in orbit around Earth, but it can also trap light for infinity in a dying star and ripple across the cosmos carrying the news of a massive collision between two distant black holes. With accessible language and breathtaking NASA images, students will explore the theory of gravity, from Newton's law of universal gravitation to Einstein's general relativity and beyond. This book supports the Next Generation Science Standards' emphasis on scientific collection and analysis of data and evidence-based theories by discussing the theoretical models scientists devise to describe gravity and the real-world experiments they use to test them.