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 Guide": "The Planets" (recordings under Boult on HMV and Nixa, and another under Sir Malcolm Sargent on Decca); the "Perfect Fool" ballet music; the "St Paul's Suite"; and three short choral pieces. In the stereo LP and CD eras numerous recordings of "The Planets" were issued, performed by orchestras and conductors from round the world. By the early years of the 21st century most of the major and many of the minor orchestral and choral works had been issued on disc. The 2008 issue of "The Penguin Guide to Recorded Classical Music" contained seven pages of listings of Holst's works