Kepler's laws of planetary motion of solar system body number "i" is, according to Newton's laws: where formula_72 is the mass of body "j", formula_73 is the distance between body "i" and body "j", formula_74 is the unit vector from body "i" towards body "j", and the vector summation is over all bodies in the world, besides "i" itself. In the special case where there are only two bodies in the world, Earth and Sun, the acceleration becomes which is the acceleration of the Kepler motion. So this Earth moves around the Sun according to Kepler's laws. If the two bodies in the world are
Clarke's three laws Clarke's three laws British science fiction writer Arthur C. Clarke formulated three adages that are known as Clarke's three laws, of which the third law is the best known and most widely cited. They were part of his ideas in his extensive writings about the future. These so-called laws include: One account claimed that Clarke's "laws" were developed after the editor of his works in French started numbering the author's assertions. All three laws appear in Clarke's essay "Hazards of Prophecy: The Failure of Imagination", first published in "Profiles of the Future" (1962). However, they were not published at the