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 compositions. In the "Two Songs without Words" of 1906, Holst showed that he could create his own original music using the folk idiom. An orchestral folksong fantasy "Songs of the West", also written in 1906, was withdrawn by the composer and never published, although it emerged in the 1980s in the form of an arrangement for wind band by James Curnow. In the years before the First World War, Holst composed in a variety of genres. Matthews considers the evocation of a North African town in the "Beni Mora" suite of 1908 the composer's most individual work to that date;