{"id":4681,"date":"2026-06-07T04:00:18","date_gmt":"2026-06-07T02:00:18","guid":{"rendered":"https:\/\/studentmag.unipr.it\/?p=4681"},"modified":"2026-06-06T16:09:28","modified_gmt":"2026-06-06T14:09:28","slug":"essere-o-non-essere-un-pianeta-la-storia-di-plutone","status":"publish","type":"post","link":"https:\/\/studentmag.unipr.it\/index.php\/2026\/06\/07\/essere-o-non-essere-un-pianeta-la-storia-di-plutone\/","title":{"rendered":"Essere o non essere (un pianeta): la storia di Plutone"},"content":{"rendered":"<div class=\"fusion-fullwidth fullwidth-box fusion-builder-row-1 fusion-flex-container has-pattern-background has-mask-background nonhundred-percent-fullwidth non-hundred-percent-height-scrolling\" style=\"--link_color: var(--awb-color4);--awb-border-radius-top-left:0px;--awb-border-radius-top-right:0px;--awb-border-radius-bottom-right:0px;--awb-border-radius-bottom-left:0px;--awb-flex-wrap:wrap;\" ><div class=\"fusion-builder-row fusion-row fusion-flex-align-items-flex-start 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);height:43px;\"><\/div><\/div><div class=\"fusion-section-separator-spacer\"><div class=\"fusion-section-separator-spacer-height\"><\/div><\/div><\/div><div class=\"fusion-separator fusion-has-icon fusion-full-width-sep\" style=\"align-self: center;margin-left: auto;margin-right: auto;width:100%;\"><div class=\"fusion-separator-border sep-single sep-dashed\" style=\"--awb-height:20px;--awb-amount:20px;border-color:var(--awb-color2);border-top-width:3px;\"><\/div><span class=\"icon-wrapper\" style=\"border-color:transparent;font-size:23px;width: 1.75em; height: 1.75em;border-width:3px;padding:3px;margin-top:-1.5px\"><i class=\"fa-angle-double-down fas\" style=\"font-size: inherit;color:var(--awb-color2);\" aria-hidden=\"true\"><\/i><\/span><div class=\"fusion-separator-border sep-single sep-dashed\" style=\"--awb-height:20px;--awb-amount:20px;border-color:var(--awb-color2);border-top-width:3px;\"><\/div><\/div><\/div><\/div><div class=\"fusion-layout-column fusion_builder_column fusion-builder-column-1 fusion_builder_column_1_1 1_1 fusion-flex-column\" style=\"--awb-bg-size:cover;--awb-width-large:100%;--awb-margin-top-large:0px;--awb-spacing-right-large:1.92%;--awb-margin-bottom-large:0px;--awb-spacing-left-large:1.92%;--awb-width-medium:100%;--awb-order-medium:0;--awb-spacing-right-medium:1.92%;--awb-spacing-left-medium:1.92%;--awb-width-small:100%;--awb-order-small:0;--awb-spacing-right-small:1.92%;--awb-spacing-left-small:1.92%;\"><div class=\"fusion-column-wrapper fusion-column-has-shadow fusion-flex-justify-content-flex-start fusion-content-layout-column\"><div class=\"fusion-text fusion-text-1\" style=\"--awb-content-alignment:justify;\"><p>Nell\u2019ultimo mese il futuro capo della NASA, <strong>Jared Isaacman<\/strong>, ha espresso la volont\u00e0 di restituire a <strong>Plutone<\/strong> lo status di pianeta. Infatti, i lettori nati prima del 2000 ricordano bene che durante la loro infanzia il Sistema solare contava nove pianeti e l\u2019ultimo di questi era proprio Plutone. Ma nel 2006 l\u2019Unione Astronomica Internazionale ha votato per una revisione del suo status, declassandolo a pianeta nano.<\/p>\n<p>La questione emerse in seguito alla scoperta di altri oggetti simili a Plutone nella stessa regione dello spazio, la Fascia di Kuiper, tra cui <strong>Eris<\/strong>, inizialmente stimato persino pi\u00f9 grande di Plutone. La presenza di questi nuovi corpi celesti poneva un problema: considerarli tutti pianeti, rendendo il Sistema solare molto pi\u00f9 affollato, oppure riconoscere che Plutone appartenesse a una categoria diversa. Serviva quindi una definizione pi\u00f9 precisa di \u201cpianeta\u201d. Cos\u00ec, nel 2006, durante l\u2019assemblea di Praga, viene approvata una nuova definizione. Un pianeta \u00e8 un corpo in orbita attorno al Sole, sufficientemente massiccio da assumere una forma quasi sferica grazie alla propria gravit\u00e0 e infine capace di \u201cripulire\u201d la propria orbita. Plutone soddisfa i primi due requisiti, ma non il terzo. Un pianeta, infatti, con la propria gravit\u00e0 domina la regione orbitale in cui si trova, inglobando o espellendo gran parte dei detriti presenti lungo il suo percorso attorno al Sole. La gravit\u00e0 di Plutone non \u00e8 sufficiente a compiere questo processo: la sua orbita attraversa infatti la Fascia di Kuiper, una vasta regione ricca di corpi ghiacciati e residui della formazione del Sistema solare. Per questa ragione Plutone viene riclassificato come pianeta nano, una nuova categoria di oggetti celesti distinta sia dai pianeti tradizionali sia dagli asteroidi.<\/p>\n<p>Il declassamento di Plutone provoca una forte indignazione soprattutto negli Stati Uniti: era infatti l\u2019unico pianeta scoperto da un astronomo americano, <strong>Clyde Tombaugh<\/strong>, e non \u00e8 quindi un caso che oggi sia ancora un americano a riaprire il dibattito. Nonostante il nuovo status, l\u2019interesse scientifico verso Plutone non si \u00e8 mai spento. Proprio nel 2006, lo stesso anno del declassamento, \u00e8 stata lanciata la missione New Horizons, progettata per esplorarlo. La sonda ha impiegato circa nove anni e mezzo per raggiungerlo e, durante il rapido sorvolo del 2015, ha inviato sulla Terra alcune delle immagini pi\u00f9 dettagliate mai ottenute di questo mondo lontano. Plutone si \u00e8 rivelato un corpo sorprendentemente complesso: un mondo ghiacciato ricoperto di valli, montagne e pianure, dotato di una sottile atmosfera e di un sistema di lune. Scoperte che hanno dimostrato come la curiosit\u00e0 verso questo piccolo mondo non si sia affatto spenta, ma continui ancora oggi ad alimentare il dibattito scientifico.<\/p>\n<p>Oggi Plutone rimane al centro dell\u2019attenzione scientifica non come semplice ex pianeta, ma come chiave per studiare le origini e la complessit\u00e0 delle regioni pi\u00f9 lontane del nostro sistema planetario. Forse, pi\u00f9 che chiedersi se Plutone sia o meno un pianeta, la domanda pi\u00f9 interessante \u00e8 quanto ancora abbia da insegnarci sul Sistema solare.<\/p>\n<\/div><\/div><\/div><\/div><\/div>\n","protected":false},"excerpt":{"rendered":"<p>Dalla decisione di declassarlo, il dibattito sulla natura del corpo spaziale non ha conosciuto requie: vediamo pi\u00f9 da vicino la sua evoluzione<\/p>\n","protected":false},"author":8,"featured_media":4682,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[25],"tags":[202],"autore":[204],"class_list":["post-4681","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-cool-tura","tag-scienza","autore-andrea-salvemini"],"acf":[],"_links":{"self":[{"href":"https:\/\/studentmag.unipr.it\/index.php\/wp-json\/wp\/v2\/posts\/4681","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/studentmag.unipr.it\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/studentmag.unipr.it\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/studentmag.unipr.it\/index.php\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/studentmag.unipr.it\/index.php\/wp-json\/wp\/v2\/comments?post=4681"}],"version-history":[{"count":3,"href":"https:\/\/studentmag.unipr.it\/index.php\/wp-json\/wp\/v2\/posts\/4681\/revisions"}],"predecessor-version":[{"id":4715,"href":"https:\/\/studentmag.unipr.it\/index.php\/wp-json\/wp\/v2\/posts\/4681\/revisions\/4715"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/studentmag.unipr.it\/index.php\/wp-json\/wp\/v2\/media\/4682"}],"wp:attachment":[{"href":"https:\/\/studentmag.unipr.it\/index.php\/wp-json\/wp\/v2\/media?parent=4681"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/studentmag.unipr.it\/index.php\/wp-json\/wp\/v2\/categories?post=4681"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/studentmag.unipr.it\/index.php\/wp-json\/wp\/v2\/tags?post=4681"},{"taxonomy":"autore","embeddable":true,"href":"https:\/\/studentmag.unipr.it\/index.php\/wp-json\/wp\/v2\/autore?post=4681"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}