Stability of the Solar System that keeps the far side of the Moon away from the Earth. Mercury is in a 3:2 spin–orbit resonance. The planets' orbits are chaotic over longer timescales, such that the whole Solar System possesses a Lyapunov time in the range of 2–230 million years. In all cases this means that the position of a planet along its orbit ultimately becomes impossible to predict with any certainty (so, for example, the timing of winter and summer become uncertain), but in some cases the orbits themselves may change dramatically. Such chaos manifests most strongly as changes in eccentricity, with some planets' orbits
The Planets: A Modern Allegory The Planets: A Modern Allegory The Planets: A Modern Allegory is a radio play, written in verse, by Alfred Kreymborg. The first performance was on 6 June 1938 by the National Broadcasting Company at the Hayden Planetarium in New York City, and was directed by Thomas L. Riley. The play was originally set to the music of "The Planets" Suite by Gustav Holst; for the first performance the NBC Symphony Orchestra was conducted by H. Leopold Spitalny. The first broadcast was so enthusiastically received that it was repeated a few weeks later. The play describes the early history of the