Stability of the Solar System essentially the distance from sun to earth). These are now known as the Kirkwood gaps. Some asteroids were later discovered to orbit in these gaps, but their orbits are unstable and they will eventually break out of the resonance due to close encounters with a major planet. Another common form of resonance in the Solar System is spin–orbit resonance, where the period of spin (the time it takes the planet or moon to rotate once about its axis) has a simple numerical relationship with its orbital period. An example is our own Moon, which is in a 1:1 spin–orbit resonance
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 An orchestral folksong fantasy "Songs of the West", also written in 1906, was withdrawn by the composer and never published, although it emerged in the 1980s in the form of an arrangement for wind band by James Curnow.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;