Solar System 7 light-years away. Compared to many other planetary systems, the Solar System stands out in lacking planets interior to the orbit of Mercury. The known Solar System also lacks super-Earths (Planet Nine could be a super-Earth beyond the known Solar System). Uncommonly, it has only small rocky planets and large gas giants; elsewhere planets of intermediate size are typical—both rocky and gas—so there is no "gap" as seen between the size of Earth and of Neptune (with a radius 3.8 times as large). Also, these super-Earths have closer orbits than Mercury. This led to hypothesis that all planetary systems start
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