Celestial mechanics Celestial mechanics Celestial mechanics is the branch of astronomy that deals with the motions of objects in outer space. Historically, celestial mechanics applies principles of physics (classical mechanics) to astronomical objects, such as stars and planets, to produce ephemeris data. As an astronomical field of study, celestial mechanics includes the sub-fields of orbital mechanics, which deals with the launching and orbits artificial satellites, and lunar theory, a specialty which deals with the complications of the orbit of the Moon. Modern celestial mechanics tends to divide between five broad fields of study: All of the above fields overlap, but are sometimes
Dynamics of the celestial spheres Dynamics of the celestial spheres Ancient, medieval and Renaissance astronomers and philosophers developed many different theories about the dynamics of the celestial spheres. They explained the motions of the various nested spheres in terms of the materials of which they were made, external movers such as celestial intelligences, and internal movers such as motive souls or impressed forces. Most of these models were qualitative, although a few of them incorporated quantitative analyses that related speed, motive force and resistance. In considering the physics of the celestial spheres, scholars followed two different views about the material composition of the celestial spheres.