The Planets dedication notwithstanding, Imogen Holst "would have been both amused and dismayed by the venture." On 24 August 2006, the International Astronomical Union (IAU) defined what it means to be a "planet" within the Solar System. This definition excluded Pluto as a planet and added it as a member of the new category of "dwarf planets", along with Eris and Ceres. Following the IAU decision, Kenyon D. Wilson composed a trombone quintet piece titled "Songs of Distant Earth". The title comes from Arthur C. Clarke's novel of the same name. The composition contains five movements, each named after one of the
Gustav Holst found his genuine voice in his setting of Whitman's verses, "The Mystic Trumpeter" (1904), in which the trumpet calls that characterise Mars in "The Planets" are briefly anticipated. In this work, Holst first employs the technique of bitonality—the use of two keys simultaneously. At the beginning of the 20th century, according to Matthews, it appeared that Holst might follow Schoenberg into late Romanticism. Instead, as Holst recognised afterwards, his encounter with Purcell's "Dido and Aeneas" prompted his searching for a "musical idiom of the English language"; the folksong revival became a further catalyst for Holst to seek inspiration from other