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,
Egdon Heath (Holst) Holst considered the work his most perfectly realised composition, an opinion shared by Ralph Vaughan Williams and others. But it has never had the profile of works such as "The Planets" and "St Paul's Suite". In 1934 Edwin Evans speculated on why the public had not yet shared the composer's assessment: Egdon Heath (Holst) Egdon Heath, Op. 47, H. 172, subtitled "A Homage to Thomas Hardy", is a tone poem by Gustav Holst, written in 1927. Holst considered it his most perfectly realised composition. Egdon Heath is a fictional place in the equally fictional region of Wessex in the south-west