Planet the Sun: Jupiter is the largest, at 318 Earth masses, whereas Mercury is the smallest, at 0.055 Earth masses. The planets of the Solar System can be divided into categories based on their composition: An exoplanet (extrasolar planet) is a planet outside the Solar System. In early 1992, radio astronomers Aleksander Wolszczan and Dale Frail announced the discovery of two planets orbiting the pulsar PSR 1257+12. This discovery was confirmed, and is generally considered to be the first definitive detection of exoplanets. These pulsar planets are believed to have formed from the unusual remnants of the supernova that produced the
Imogen Holst by the cellist Steven Isserlis. In 1976, she took legal action over a recording by Japanese electronic composer Isao Tomita of 'The Planets', calling it 'unworthy of my father's creation'. The record, originally issued on the RCA label, was withdrawn from sale, and vinyl copies have subsequently become very rare. In April 1979 Holst was present when the Queen Mother opened the new Britten–Pears School building in Snape. The building included a new library—the Gustav Holst Library—to which Holst had donated a large amount of material, including books which her father had used in his own teaching career. She had