The Gravity and Orbits Interactive E-book* investigates concepts related to Earth’s universal gravitation and how gravity affects the universe around us. All objects that have mass have a gravitational force and every object exerts a gravitational force on every other object. The force is hard to detect unless at least one of the objects has a lot of mass. Distance also influences the strength of gravitational force. We see the effects of gravity on Earth as well as in how objects with mass interact in space. Gravity is the force behind the falling rain and flowing rivers, is responsible for pulling the matter that makes up planets and stars toward their centers to form spheres, and keeps satellites, planets, and moons in orbit around celestial bodies.
*Interactive E-books are highly interactive, self-directed learning experiences designed to augment understanding of science content and pedagogy. These e-books include high-resolution images, animations, videos and interactive simulations.