Newton's theorem of revolving orbits does not go to infinity. However, this conclusion holds only when two bodies are present (the two-body problem); the motion of three bodies or more acting under their mutual gravitation (the "n"-body problem) remained unsolved for centuries after Newton, although solutions to a few special cases were discovered. Newton proposed that the orbits of planets about the Sun are largely elliptical because the Sun's gravitation is dominant; to first approximation, the presence of the other planets can be ignored. By analogy, the elliptical orbit of the Moon about the Earth was dominated by the Earth's gravity; to first approximation, the
Clarke's three laws into any typeface and size from Albertus Extra Bold to Zurich Calligraphic", referring to his memory of "seeing and hearing Linotype machines which slowly converted ‘molten lead into front pages that required two men to lift them’". A fourth law has been proposed for the canon, despite Clarke's declared intention of stopping at three laws. Geoff Holder quotes: "For every expert, there is an equal and opposite expert," which is part of American economist Thomas Sowell's "For every expert, there is an equal and opposite expert, but for every fact there is not necessarily an equal and opposite fact", from