Terrestrial planet from the original solar nebula. The Solar System has four terrestrial planets: Mercury, Venus, Earth, and Mars. Only one terrestrial planet, Earth, is known to have an active hydrosphere. During the formation of the Solar System, there were probably many more terrestrial planetesimals, but most merged with or were ejected by the four terrestrial planets. Dwarf planets, such as Ceres, Pluto and Eris, and small Solar System bodies are similar to terrestrial planets in the fact that they do have a solid surface, but are, on average, composed of more icy materials (Ceres, Pluto and Eris have densities of 2.17,
Gustav Holst he and other younger English composers had adopted Holst's economy of style: "With what enthusiasm did we pare down our music to the very bone". Short cites other English composers who are in debt to Holst, in particular William Walton and Benjamin Britten, and suggests that Holst's influence may have been felt further afield. Above all, Short recognises Holst as a composer for the people, who believed it was a composer's duty to provide music for practical purposes—festivals, celebrations, ceremonies, Christmas carols or simple hymn tunes. Thus, says Short, "many people who may never have heard any of [Holst's] major