Planets beyond Neptune tiny, tiny, field of view, that would suggest that there are something like 200,000 Earth-sized planets in the outer Solar System ... Even better, I just realized that this many Earth-sized planets existing would destabilize the entire Solar System and we would all die." As of 2016 the following observations severely constrain the mass and distance of any possible additional Solar System planet: Planets beyond Neptune Following the discovery of the planet Neptune in 1846, there was considerable speculation that another planet might exist beyond its orbit. The search began in the mid-19th century and continued at the start of
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