Gravity, as most people understand it, is the familiar force that pulls a falling apple toward Earth. But for astronomers and theoretical physicists, it is also a vexing invisible architect that guides the shape and evolution of the largest cosmic structures across the universe. Gravity, as most people understand it, is the familiar force that pulls a falling apple toward Earth. But for astronomers and theoretical physicists, it is also a vexing invisible architect that guides the shape and evolution of the largest cosmic st... [4796 chars]