{"id":372175,"date":"2026-09-19T14:23:00","date_gmt":"2026-09-19T08:53:00","guid":{"rendered":"https:\/\/forumias.com\/blog\/?p=372175"},"modified":"2026-09-19T14:23:00","modified_gmt":"2026-09-19T08:53:00","slug":"definition-of-a-planet-and-pluto","status":"publish","type":"post","link":"https:\/\/forumias.com\/blog\/definition-of-a-planet-and-pluto\/","title":{"rendered":"Definition of a \u2018Planet\u2019 and Pluto"},"content":{"rendered":"<div class=\"content-box-green\">\n<p><b>News: <\/b>New Horizons\u2019 probe 2015 discoveries and images captured of Pluto has renewed debate over definition of a \u2018Planet\u2019 and Pluto as a planet.<\/p>\n<\/div>\n<h2 class=\"red-h2-box\"><b>\u00a0About Definition of a \u2018Planet\u2019 and Pluto<\/b><\/h2>\n<figure style=\"width: 314px\" class=\"wp-caption aligncenter\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" src=\"https:\/\/i0.wp.com\/cdn.mos.cms.futurecdn.net\/eux6F3aezJEuwCYode2EfZ.jpg?resize=314%2C333&#038;ssl=1\" alt=\"definition of planet\" width=\"314\" height=\"333\" \/><figcaption class=\"wp-caption-text\">Source: SPACE<\/figcaption><\/figure>\n<ul>\n<li><b>In 2006<\/b><span style=\"font-weight: 400;\">, the <strong>International Astronomical Union (IAU)<\/strong> met in Prague to decide what exactly should be called a <\/span><b>planet<\/b><span style=\"font-weight: 400;\">.<\/span><\/li>\n<li><b>Condition for recognition as planet:<\/b><span style=\"font-weight: 400;\"> It was decided by IAU that a <strong>planet<\/strong> must satisfy <\/span><b>three conditions<\/b><span style=\"font-weight: 400;\">:<\/span>\n<ul>\n<li><span style=\"font-weight: 400;\">It must <\/span><b>orbit the Sun<\/b><span style=\"font-weight: 400;\">.<\/span><\/li>\n<li><b>Sufficient mass for its self-gravity <\/b><span style=\"font-weight: 400;\">to overcome rigid body forces so that it assumes a <\/span><b>hydrostatic equilibrium (nearly round) shape.<\/b><\/li>\n<li><span style=\"font-weight: 400;\">An<\/span><b> orbital path clear of other celestial objects.<\/b><\/li>\n<\/ul>\n<\/li>\n<li><b>Case of Pluto: Pluto <\/b>met the<b> first two conditions, but failed the third condition<\/b><span style=\"font-weight: 400;\"> because <\/span><b>it shares its orbital region <\/b><span style=\"font-weight: 400;\">with many other objects in the <\/span><b>Kuiper Belt. <\/b><span style=\"font-weight: 400;\">Therefore, it was classified <\/span><b>as a \u201cdwarf planet in 2006.\u201d\u00a0<\/b>\n<ul>\n<li><strong>A &#8216;dwarf planet&#8217;<\/strong> is a <strong>celestial body<\/strong> that\n<ul>\n<li>is in <strong>orbit around the Sun<\/strong>,<\/li>\n<li>has <strong>sufficient mass<\/strong> for its <strong>self-gravity<\/strong> to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape,<\/li>\n<li>has <strong>not cleared the neighborhood<\/strong> around its orbit, and<\/li>\n<li>is <strong>not a satellite<\/strong>.<\/li>\n<\/ul>\n<\/li>\n<li><span style=\"font-weight: 400;\">It is recognized as the <\/span><b>prototype of a new category of trans-Neptunian objects.<\/b><\/li>\n<\/ul>\n<\/li>\n<li><strong>Present situation:<\/strong> The <strong data-start=\"1004\" data-end=\"1028\">New Horizons mission<\/strong>, which reached Pluto in 2015, revealed that Pluto has <strong data-start=\"1083\" data-end=\"1190\">nitrogen-ice glaciers, large mountains, a layered atmosphere, active geological features and five moons<\/strong>.\n<ul>\n<li style=\"list-style-type: none;\">\n<ul>\n<li>These discoveries<strong>\u00a0renewed discussion<\/strong> about<strong> whether the existing definition adequately represents what a planet is.<\/strong><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<table style=\"border-style: solid;\">\n<tbody>\n<tr>\n<td>\n<h2 class=\"red-h2-box\"><strong>About the International Astronomical Union (IAU)<\/strong><\/h2>\n<ul>\n<li style=\"font-weight: 400;\"><b>About:<\/b> <span style=\"font-weight: 400;\">IAU is a <\/span><span style=\"font-weight: 400;\">global<strong> organization of professional astronomers,<\/strong><\/span><span style=\"font-weight: 400;\"> at the PhD level and beyond who are active in professional education and research in astronomy.<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>Origin:<\/b> <span style=\"font-weight: 400;\">It was <\/span><strong>founded in 1919.<\/strong><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\"><strong>Headquarters:<\/strong> Its <\/span><span style=\"font-weight: 400;\">headquarter<\/span><span style=\"font-weight: 400;\"> is in <\/span><strong>Paris, France.<\/strong><\/li>\n<li style=\"font-weight: 400;\"><b>Objective:<\/b> <span style=\"font-weight: 400;\">Its o<\/span><span style=\"font-weight: 400;\">bjective <\/span><span style=\"font-weight: 400;\">is <strong>to <\/strong><\/span><strong>promote and safeguard the science of astronomy in all its aspects<\/strong><span style=\"font-weight: 400;\"><strong>,<\/strong> including research, communication, education and development, through international cooperation.<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>Members:<\/b><span style=\"font-weight: 400;\"> It has<\/span><strong> 92 member countries,<\/strong><span style=\"font-weight: 400;\"> wi<strong>th 85 being National Members.<\/strong> It also <\/span><span style=\"font-weight: 400;\">collaborates with scientific organizations<\/span><span style=\"font-weight: 400;\"> globally.<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>Mandate: <\/b><span style=\"font-weight: 400;\">It is the<\/span><span style=\"font-weight: 400;\"> i<strong>nternationally recognized authority for assigning designations to celestial bodies <\/strong><\/span><span style=\"font-weight: 400;\">(stars, planets, asteroids, etc.) and any surface features on them.<\/span><\/li>\n<\/ul>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"excerpt":{"rendered":"<p>News: New Horizons\u2019 probe 2015 discoveries and images captured of Pluto has renewed debate over definition of a \u2018Planet\u2019 and Pluto as a planet. \u00a0About Definition of a \u2018Planet\u2019 and Pluto In 2006, the International Astronomical Union (IAU) met in Prague to decide what exactly should be called a planet. Condition for recognition as planet:&hellip; <a class=\"more-link\" href=\"https:\/\/forumias.com\/blog\/definition-of-a-planet-and-pluto\/\">Continue reading <span class=\"screen-reader-text\">Definition of a \u2018Planet\u2019 and Pluto<\/span><\/a><\/p>\n","protected":false},"author":10366,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"footnotes":""},"categories":[1566,1738,12039],"tags":[11872,10504],"class_list":["post-372175","post","type-post","status-publish","format-standard","hentry","category-daily-factly-articles","category-science-and-technology-daily-factly-articles","category-knolls","tag-9pm-daily-factly","tag-down-to-earth","entry"],"jetpack_featured_media_url":"","views":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/forumias.com\/blog\/wp-json\/wp\/v2\/posts\/372175","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/forumias.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/forumias.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/forumias.com\/blog\/wp-json\/wp\/v2\/users\/10366"}],"replies":[{"embeddable":true,"href":"https:\/\/forumias.com\/blog\/wp-json\/wp\/v2\/comments?post=372175"}],"version-history":[{"count":0,"href":"https:\/\/forumias.com\/blog\/wp-json\/wp\/v2\/posts\/372175\/revisions"}],"wp:attachment":[{"href":"https:\/\/forumias.com\/blog\/wp-json\/wp\/v2\/media?parent=372175"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/forumias.com\/blog\/wp-json\/wp\/v2\/categories?post=372175"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/forumias.com\/blog\/wp-json\/wp\/v2\/tags?post=372175"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}