{"id":59,"date":"2008-06-12T10:45:57","date_gmt":"2008-06-12T15:45:57","guid":{"rendered":"http:\/\/blog.richmond.edu\/physicsbunn\/2008\/06\/12\/plutoids\/"},"modified":"2008-06-12T10:45:57","modified_gmt":"2008-06-12T15:45:57","slug":"plutoids","status":"publish","type":"post","link":"https:\/\/blog.richmond.edu\/physicsbunn\/2008\/06\/12\/plutoids\/","title":{"rendered":"Plutoids"},"content":{"rendered":"

According to the International Astronomical Union, Pluto is still not a planet, but it is a Plutoid<\/a>.\u00a0 If I recall correctly, at the time the original naming decision was made, there was a proposal to call the class of Pluto-like objects “Plutons,” but that was rejected, in part because “Pluton” is already the name of Pluto in various languages, including French.\u00a0 I guess “Plutoid” solves that problem.<\/p>\n

I don’t much care about Pluto no longer being considered a planet, but I do think that the IAU made a poor choice of naming conventions.\u00a0 According to the new system, Pluto and similar objects are not planets, but they are “dwarf planets.”\u00a0 That’s right: a dwarf planet is not a planet.\u00a0 That’s a needlessly confusing naming convention, especially since it’s inconsistent with the terminology in the rest of astronomy: dwarf stars are stars, and dwarf galaxies are galaxies.<\/p>\n

That’s old news now, of course: the new wrinkle, namely the introduction of the term “Plutoid,” neither solves nor worsens that problem.<\/p>\n

Even though it’s all in the past, here are a couple of observations about the Pluto-classification flap:<\/p>\n

1. Obviously, no interesting scientific questions hinge on whether we choose to classify Pluto as a planet.\u00a0 I recall a news article at the time of the Great Naming Controversy saying that the future of NASA’s New Horizons probe was in doubt because of the reclassification of Pluto as a non-planet.\u00a0 That’s an obviously ridiculous notion: As Abraham Lincoln<\/a> could tell you, the nature of a thing doesn’t change because of what we call it.<\/p>\n

2.\u00a0 The justification for the Great Renaming was to have a precise physical definition of the word “planet.”\u00a0 Mike Brown<\/a> has argued against the need for such a definition: Why not just consider the word “planet” to mean the nine bodies that it has traditionally meant?\u00a0 By way of analogy, the word “continent” refers to a conventional set of seven land masses.\u00a0 We don’t really need to justify why it’s that list of seven (Why aren’t Europe and Asia considered as one? Why not include Greenland?). \u00a0 Often, science needs precise, objective definitions in order to proceed.\u00a0 But it’s not clear that in this case anyone was being hampered by the arbitrary nine-body definition of the word “planet.”\u00a0 What, exactly, was the problem that the IAU solved?<\/p>\n","protected":false},"excerpt":{"rendered":"

According to the International Astronomical Union, Pluto is still not a planet, but it is a Plutoid.\u00a0 If I recall correctly, at the time the original naming decision was made, there was a proposal to call the class of Pluto-like objects “Plutons,” but that was rejected, in part because “Pluton” is already the name of … Continue reading Plutoids<\/span><\/a><\/p>\n","protected":false},"author":12,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-59","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/blog.richmond.edu\/physicsbunn\/wp-json\/wp\/v2\/posts\/59","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.richmond.edu\/physicsbunn\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.richmond.edu\/physicsbunn\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.richmond.edu\/physicsbunn\/wp-json\/wp\/v2\/users\/12"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.richmond.edu\/physicsbunn\/wp-json\/wp\/v2\/comments?post=59"}],"version-history":[{"count":0,"href":"https:\/\/blog.richmond.edu\/physicsbunn\/wp-json\/wp\/v2\/posts\/59\/revisions"}],"wp:attachment":[{"href":"https:\/\/blog.richmond.edu\/physicsbunn\/wp-json\/wp\/v2\/media?parent=59"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.richmond.edu\/physicsbunn\/wp-json\/wp\/v2\/categories?post=59"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.richmond.edu\/physicsbunn\/wp-json\/wp\/v2\/tags?post=59"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}