{"id":2133,"date":"2019-10-28T09:48:00","date_gmt":"2019-10-28T08:48:00","guid":{"rendered":"http:\/\/astroaspach.fr\/astroaspachV2\/?p=2133"},"modified":"2020-10-28T09:51:07","modified_gmt":"2020-10-28T08:51:07","slug":"thuban-et-la-precession-des-equinoxes","status":"publish","type":"post","link":"http:\/\/astroaspach.fr\/astroaspachV2\/2019\/10\/28\/thuban-et-la-precession-des-equinoxes\/","title":{"rendered":"Thuban et la pr\u00e9cession des \u00e9quinoxes"},"content":{"rendered":"<p>\u03b1 Draconis (Alpha Draconis) ou\u00a0 Thuban n&rsquo;est pas l&rsquo;\u00e9toile la plus brillante de la constellation du Dragon. Son \u00e9clat n&rsquo;est n&rsquo;est que le 8\u00e8me de cette constellation qui serpente entre les constellations de la Grande Ourse, de la Petite Ourse et de la Lyre. C&rsquo;est pourtant sans doute son \u00e9toile plus connue .<\/p>\n<p><a href=\"http:\/\/astroaspach.fr\/astroaspachV2\/wp-content\/uploads\/2020\/10\/thuban03.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-2132 size-full\" src=\"http:\/\/astroaspach.fr\/astroaspachV2\/wp-content\/uploads\/2020\/10\/thuban03.jpg\" alt=\"\" width=\"800\" height=\"444\" srcset=\"http:\/\/astroaspach.fr\/astroaspachV2\/wp-content\/uploads\/2020\/10\/thuban03.jpg 800w, http:\/\/astroaspach.fr\/astroaspachV2\/wp-content\/uploads\/2020\/10\/thuban03-300x167.jpg 300w, http:\/\/astroaspach.fr\/astroaspachV2\/wp-content\/uploads\/2020\/10\/thuban03-768x426.jpg 768w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><\/a><\/p>\n<p>En effet, il y a 4800 ans, l&rsquo;axe p\u00f4le nord &#8211; p\u00f4le sud de la terre pointait vers cette \u00e9toile, qui \u00e9tait alors l&rsquo;\u00e9toile polaire. Depuis, par le mouvement de \u00ab\u00a0pr\u00e9cession des \u00e9quinoxes\u00a0\u00bb, c&rsquo;est \u03b1 Ursae minoris, \u00e9toile de la constellation de la petite ourse qui est devenue l&rsquo;\u00e9toile polaire.<\/p>\n<p>Mais qu&rsquo;est donc la \u00ab\u00a0pr\u00e9cession des \u00e9quinoxes\u00a0\u00bb ? L&rsquo;image d&rsquo;une toupie qui tourne sur elle m\u00eame est famili\u00e8re, mais en plus de tourner sur elle m\u00eame, l&rsquo;axe de rotation de la toupie d\u00e9crit un c\u00f4ne donc la pointe pose sur le sol. Pour la terre, c&rsquo;est pareil, l&rsquo;axe p\u00f4le nord &#8211; p\u00f4le sud d\u00e9crit un cercle dans le firmaments des \u00e9toiles. Dans 12000 ans, l&rsquo;\u00e9toile polaire sera V\u00e9ga de la constellation de la Lyre, il faut 26000 ans \u00e0 l&rsquo;axe pour faire un tour complet.<\/p>\n<p><a href=\"http:\/\/astroaspach.fr\/astroaspachV2\/wp-content\/uploads\/2020\/10\/thuban.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-2131 size-full\" src=\"http:\/\/astroaspach.fr\/astroaspachV2\/wp-content\/uploads\/2020\/10\/thuban.jpg\" alt=\"\" width=\"614\" height=\"600\" srcset=\"http:\/\/astroaspach.fr\/astroaspachV2\/wp-content\/uploads\/2020\/10\/thuban.jpg 614w, http:\/\/astroaspach.fr\/astroaspachV2\/wp-content\/uploads\/2020\/10\/thuban-300x293.jpg 300w\" sizes=\"auto, (max-width: 614px) 100vw, 614px\" \/><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p><a href=\"http:\/\/astroaspach.fr\/astroaspachV2\/wp-content\/uploads\/2020\/10\/thuban03.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignleft wp-image-2132\" src=\"http:\/\/astroaspach.fr\/astroaspachV2\/wp-content\/uploads\/2020\/10\/thuban03-300x167.jpg\" alt=\"\" width=\"100\" height=\"55\" srcset=\"http:\/\/astroaspach.fr\/astroaspachV2\/wp-content\/uploads\/2020\/10\/thuban03-300x167.jpg 300w, http:\/\/astroaspach.fr\/astroaspachV2\/wp-content\/uploads\/2020\/10\/thuban03-768x426.jpg 768w, http:\/\/astroaspach.fr\/astroaspachV2\/wp-content\/uploads\/2020\/10\/thuban03.jpg 800w\" sizes=\"auto, (max-width: 100px) 100vw, 100px\" \/><\/a><br \/>\nIl y a 4800 ans, Thuban \u00e9tait l&rsquo;\u00e9toile polaire de la Terre !<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[],"class_list":["post-2133","post","type-post","status-publish","format-standard","hentry","category-raconter-le-ciel"],"_links":{"self":[{"href":"http:\/\/astroaspach.fr\/astroaspachV2\/wp-json\/wp\/v2\/posts\/2133","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/astroaspach.fr\/astroaspachV2\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/astroaspach.fr\/astroaspachV2\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/astroaspach.fr\/astroaspachV2\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/astroaspach.fr\/astroaspachV2\/wp-json\/wp\/v2\/comments?post=2133"}],"version-history":[{"count":7,"href":"http:\/\/astroaspach.fr\/astroaspachV2\/wp-json\/wp\/v2\/posts\/2133\/revisions"}],"predecessor-version":[{"id":2140,"href":"http:\/\/astroaspach.fr\/astroaspachV2\/wp-json\/wp\/v2\/posts\/2133\/revisions\/2140"}],"wp:attachment":[{"href":"http:\/\/astroaspach.fr\/astroaspachV2\/wp-json\/wp\/v2\/media?parent=2133"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/astroaspach.fr\/astroaspachV2\/wp-json\/wp\/v2\/categories?post=2133"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/astroaspach.fr\/astroaspachV2\/wp-json\/wp\/v2\/tags?post=2133"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}