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 in such a role. He formally changed "von Holst" to "Holst" by deed poll in September 1918. He was appointed as the YMCA's musical organiser for the Near East, based in Salonica. Holst was given a spectacular send-off. The conductor Adrian Boult recalled, "Just before the Armistice, Gustav Holst burst into my office: 'Adrian, the YMCA are sending me to Salonica quite soon and Balfour Gardiner, bless his heart, has given me a parting present consisting of the Queen's Hall, full of the Queen's Hall Orchestra for the whole of a Sunday morning. So we're going to do "The Planets",