The Solar System Basic Structure of the Solar System Sun is in the center.
Planets orbit the sun.
Some planets have moons that orbit that planet just as the moon orbits the earth. Kepler's Three Laws of Planetary Motion describes the motion of planets, comets and asteroids around the sun as well as natural moons and artificial satellites around a planet. The path of a planet around the sun is an ellipse, with the sun at one focus. The orbital speed of a planet changes so that an imaginary line connecting the planets to the sun sweeps out equal areas in equal intervals of time. The orbital period squared is equal to the cube of the average distance of the planet to the sun.