The universe contains just two things: matter and energy. Matter makes up almost everything imaginable: furniture, food, houses, rocks, living organism, and the whole Earth. Energy is not as easy to see, but it powers race cars, makes living things move, and travels distances ranging from the confines of an atom to the ends of the universe. In Matter and Energy, readers will learn about the many forms of energy, the wide variety of particles in nature, and Albert Einstein's world-changing realization of how matter can be changed into pure energy. The book also examines the recent discoveries of dark matter and dark energy and the future of the universe.