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 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