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
Gustav Holst Guide": "The Planets" (recordings under Boult on HMV and Nixa, and another under Sir Malcolm Sargent on Decca); the "Perfect Fool" ballet music; the "St Paul's Suite"; and three short choral pieces. In the stereo LP and CD eras numerous recordings of "The Planets" were issued, performed by orchestras and conductors from round the world. By the early years of the 21st century most of the major and many of the minor orchestral and choral works had been issued on disc. The 2008 issue of "The Penguin Guide to Recorded Classical Music" contained seven pages of listings of Holst's works