The Planets, Op. 32 is a seven-movement orchestral suite by the British composer Gustav Holst, written between 1914 and 1916. Each movement of the suite is named after a planet of the Solar System and its corresponding astrological character as defined by Holst. All planets are represented with the only exception being Earth (which is not observed in astrological practice).
From its premiere to the present day, the suite has been enduringly popular, influential, widely performed and the subject of numerous recordings. However, it had a protracted birth. There were at least three performances in London and Birmingham between September 1918 and October 1920, but they were either private or incomplete. The first complete public performance was given in London on 15 November 1920, with the London Symphony Orchestra conducted by Albert Coates.
because the observability from Earth defines the Earth as not part of it
The usage of observability on Andromeda from it defines the Milky way as not part of it: