(dwarf). Thus, the term could suggest that a dwarf planet is a type of planet, even though the IAU explicitly defines a dwarf planet as not so being. By this formulation therefore, 'dwarf planet' and 'minor planet' are best considered compound nouns. Benjamin Zimmer of Language Log summarised the confusion: "The fact that the IAU would like us to think of dwarf planets as distinct from 'real' planets lumps the lexical item 'dwarf planet' in with such oddities as 'Welsh rabbit' (not really a rabbit) and 'Rocky Mountain oysters' (not really oysters)." As Dava Sobel, the historian and popular science writer who participated in the IAU's initial decision in October 2006, noted in an interview with National Public Radio, "A dwarf planet is not a planet, and in astronomy, there are dwarf stars, which are stars, and dwarf galaxies, which are galaxies, so it's a term no one can love, dwarf planet." Mike Brown noted in an interview with the Smithsonian that "Most of the people in the dynamical camp really did not want the word 'dwarf planet', but that was forced through by the pro-Pluto camp. So you're left with this ridiculous baggage of dwarf planets not being planets." Conversely, astronomer Robert Cumming of the Stockholm Observatory notes that, "The name 'minor planet' [has] been more or less synonymous with 'asteroid' for a very long time. So it seems to me pretty insane to complain about any ambiguity or risk for confusion with the introduction of 'dwarf planet'." See also Notes Defined as the region occupied by two bodies whose orbits cross a common distance from the Sun, if their orbital periods differ less than an order of magnitude. In other words, if two bodies occupy the same distance from the Sun at one point in their orbits, and those orbits are of similar size, rather than, as a comet's would be, extending for several times the other's distance, then they are in the same orbital zone. In 2002, in collaboration with dynamicist Harold Levison, Stern wrote, "we define an überplanet as a planetary body in orbit around a star that is dynamically important enough to have cleared its neighboring planetesimals ... And we define an unterplanet as one that has not been able to do so," and then a few paragraphs later, "our Solar System clearly contains 8 überplanets and a far larger number of unterplanets, the largest