Stability of the Solar System is unlikely any of the planets will collide with each other or be ejected from the system in the next few billion years, and the Earth's orbit will be relatively stable. Since Newton's law of gravitation (1687), mathematicians and astronomers (such as Laplace, Lagrange, Gauss, Poincaré, Kolmogorov, Vladimir Arnold and Jürgen Moser) have searched for evidence for the stability of the planetary motions, and this quest led to many mathematical developments, and several successive 'proofs' of stability of the Solar System. The orbits of the planets are open to long-term variations. Modeling the Solar System is a case of the
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",