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
Gustav Holst mer". Holst began composing "The Planets" in 1914; the movements appeared not quite in their final sequence; "Mars" was the first to be written, followed by "Venus" and "Jupiter". "Saturn", "Uranus" and "Neptune" were all composed during 1915, and "Mercury" was completed in 1916. Each planet is represented with a distinct character; Dickinson observes that "no planet borrows colour from another". In "Mars", a persistent, uneven rhythmic cell consisting of five beats, combined with trumpet calls and harmonic dissonance provides battle music which Short asserts is unique in its expression of violence and sheer terror, "... Holst's intention being to