It applies to any satellite orbiting any parent body, whether a planet, moon, or artificial satellite - including our geosynchronous or geostationary satellites in equatorial orbits, each of them hanging above a particular point on the equator, keeping pace with the earth's rotation and bringing us the wonders of television. Kepler considered the following questions and proposed their answers. The sun, fixed stars, earth and planets, corresponding to the Holy Trinity. The sun is the source of heat and light, and the principal source of the movement of the planets. No, orbits are elliptical.
Larger planets are farther from the sun.
About 4,000,000 diameters of the sun. No, the sun is brighter. As Imperial Mathematician, Kepler was expected to cast horoscopes, which he did to make money. He considered astrology to be mere superstition. Galileo, Kepler's contemporary, was slower to adopt the views of Copernicus, that the sun was the center of the universe.