Geology of solar terrestrial planets Geology of solar terrestrial planets The geology of solar terrestrial planets mainly deals with the geological aspects of the four terrestrial planets of the Solar System – Mercury, Venus, Earth, and Mars – and one terrestrial dwarf planet: Ceres. Earth is the only terrestrial planet known to have an active hydrosphere. Terrestrial planets are substantially different from the giant planets, which might not have solid surfaces and are composed mostly of some combination of hydrogen, helium, and water existing in various physical states. Terrestrial planets have a compact, rocky surfaces, and Venus, Earth, and Mars each also have an atmosphere.
Gustav Holst likens to "unresolved timelessness ... never ending, since space does not end, but drifting away into eternal silence". Apart from his concession with "I Vow to Thee..."', Holst insisted on the unity of the whole work, and opposed the performance of individual movements. Nevertheless, Imogen wrote that the piece had "suffered from being quoted in snippets as background music". During and after the composition of "The Planets", Holst wrote or arranged numerous vocal and choral works, many of them for the wartime Thaxted Whitsun Festivals, 1916–18. They include the "Six Choral Folksongs" of 1916, based on West Country tunes, of