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 to another house in Cheltenham, where Adolph recruited his sister Nina to help raise the boys. Gustav recognised her devotion to the family and dedicated several of his early compositions to her. In 1885 Adolph married Mary Thorley Stone, another of his pupils. They had two sons, Matthias (known as "Max") and Evelyn ("Thorley"). Mary von Holst was absorbed in theosophy and not greatly interested in domestic matters. All four of Adolph's sons were subject to what one biographer calls "benign neglect", and Gustav in particular was "not overburdened with attention or understanding, with a weak sight and a weak