{"id":3705,"date":"2026-10-04T19:45:56","date_gmt":"2026-10-04T18:45:56","guid":{"rendered":"https:\/\/www.laurensoff.com\/wordpress\/?p=3705"},"modified":"2026-10-04T19:45:56","modified_gmt":"2026-10-04T18:45:56","slug":"un-asteroide-va-t-il-secraser-sur-la-terre-quest-ce-qui-va-se-passer-le-13-avril-2029","status":"publish","type":"post","link":"https:\/\/www.laurensoff.com\/wordpress\/un-asteroide-va-t-il-secraser-sur-la-terre-quest-ce-qui-va-se-passer-le-13-avril-2029\/","title":{"rendered":"Un ast\u00e9ro\u00efde va-t-il s&#8217;\u00e9craser sur la Terre Qu&#8217;est-ce qui va se passer le 13 avril 2029 ?"},"content":{"rendered":"<p id=\"p-rc_b428fb624674cf5b-56\" data-path-to-node=\"0\"><b data-path-to-node=\"0\" data-index-in-node=\"0\"><span class=\"citation-76\">2004 MN4<\/span><\/b><span class=\"citation-76\"> est la d\u00e9signation provisoire de l&#8217;ast\u00e9ro\u00efde aujourd&#8217;hui officiellement nomm\u00e9 <\/span><b data-path-to-node=\"0\" data-index-in-node=\"87\"><span class=\"citation-76\">(99942) Apophis<\/span><\/b><span class=\"citation-76 citation-end-76\">.<\/span><\/p>\n<p id=\"p-rc_b428fb624674cf5b-57\" data-path-to-node=\"1\">C&#8217;est l&#8217;un des g\u00e9ocroiseurs les plus m\u00e9diatis\u00e9s de l&#8217;histoire de l&#8217;astronomie. <span class=\"citation-75\">Mesurant environ <\/span><b data-path-to-node=\"1\" data-index-in-node=\"96\"><span class=\"citation-75\">340 m\u00e8tres de diam\u00e8tre<\/span><\/b><span class=\"citation-75 citation-end-75\">, il a temporairement suscit\u00e9 de fortes inqui\u00e9tudes lors de sa red\u00e9couverte fin 2004 en raison d&#8217;un risque \u00e9lev\u00e9 d&#8217;impact calcul\u00e9 pour le si\u00e8cle \u00e0 venir.<\/span><\/p>\n<h3 id=\"p-rc_b428fb624674cf5b-58\" data-path-to-node=\"2\"><span class=\"citation-74 citation-end-74\">La frayeur de 2004<\/span><\/h3>\n<p data-path-to-node=\"3\">Lors des premiers calculs d&#8217;orbite en d\u00e9cembre 2004, les scientifiques ont estim\u00e9 \u00e0 pr\u00e8s de <b data-path-to-node=\"3\" data-index-in-node=\"92\">1 sur 37 (environ 2,7 %)<\/b> le risque que cet ast\u00e9ro\u00efde percute la Terre le <b data-path-to-node=\"3\" data-index-in-node=\"165\">vendredi 13 avril 2029<\/b>.<\/p>\n<p id=\"p-rc_b428fb624674cf5b-59\" data-path-to-node=\"4\"><span class=\"citation-73\">C&#8217;est le seul objet c\u00e9leste \u00e0 avoir jamais atteint le <\/span><b data-path-to-node=\"4\" data-index-in-node=\"54\"><span class=\"citation-73\">niveau 4 sur l&#8217;\u00e9chelle de Turin<\/span><\/b><span class=\"citation-73 citation-end-73\"> (qui \u00e9value le risque d&#8217;impact).<\/span> Des observations ult\u00e9rieures ont toutefois permis de pr\u00e9ciser sa trajectoire et d&#8217;\u00e9carter d\u00e9finitivement tout risque de collision pour 2029, ainsi que pour ses passages suivants en 2036 et 2068.<\/p>\n<h3 id=\"p-rc_b428fb624674cf5b-60\" data-path-to-node=\"5\"><span class=\"citation-72 citation-end-72\">Le survol historique du 13 avril 2029<\/span><\/h3>\n<p data-path-to-node=\"6\">Bien qu&#8217;il n&#8217;y ait pas d&#8217;impact, le passage de 2029 reste un \u00e9v\u00e9nement exceptionnel :<\/p>\n<ul data-path-to-node=\"7\">\n<li>\n<p data-path-to-node=\"7,0,0\"><b data-path-to-node=\"7,0,0\" data-index-in-node=\"0\">Proximit\u00e9 extr\u00eame :<\/b> Apophis va fr\u00f4ler la Terre \u00e0 environ <b data-path-to-node=\"7,0,0\" data-index-in-node=\"57\">31 600 km<\/b> de la surface, soit plus pr\u00e8s que les satellites g\u00e9ostationnaires.<\/p>\n<\/li>\n<li>\n<p id=\"p-rc_b428fb624674cf5b-61\" data-path-to-node=\"7,1,0\"><b data-path-to-node=\"7,1,0\" data-index-in-node=\"0\"><span class=\"citation-71 citation-end-71\">Visibilit\u00e9 :<\/span><\/b> Il sera visible <b data-path-to-node=\"7,1,0\" data-index-in-node=\"29\">\u00e0 l&#8217;\u0153il nu<\/b> depuis une partie de l&#8217;Europe, de l&#8217;Afrique et de l&#8217;Asie sous la forme d&#8217;un point lumineux se d\u00e9pla\u00e7ant rapidement.<\/p>\n<\/li>\n<li>\n<p id=\"p-rc_b428fb624674cf5b-62\" data-path-to-node=\"7,2,0\"><b data-path-to-node=\"7,2,0\" data-index-in-node=\"0\">Opportunit\u00e9 scientifique :<\/b> <span class=\"citation-70 citation-end-70\">La gravit\u00e9 terrestre va d\u00e9former et modifier l&#8217;orbite de l&#8217;ast\u00e9ro\u00efde.<\/span> Plusieurs agences spatiales pr\u00e9parent des missions pour l&#8217;\u00e9tudier de pr\u00e8s (comme la sonde OSIRIS-APEX de la NASA ou le projet RAMSES de l&#8217;ESA).<\/p>\n<\/li>\n<\/ul>\n<h3 data-path-to-node=\"8\">Caract\u00e9ristiques physiques<\/h3>\n<ul data-path-to-node=\"9\">\n<li>\n<p id=\"p-rc_b428fb624674cf5b-63\" data-path-to-node=\"9,0,0\"><b data-path-to-node=\"9,0,0\" data-index-in-node=\"0\"><span class=\"citation-69 citation-end-69\">Structure :<\/span><\/b> Ast\u00e9ro\u00efde rocheux de type Sq (riche en silicates et en m\u00e9taux).<\/p>\n<\/li>\n<li>\n<p id=\"p-rc_b428fb624674cf5b-64\" data-path-to-node=\"9,1,0\"><b data-path-to-node=\"9,1,0\" data-index-in-node=\"0\"><span class=\"citation-68 citation-end-68\">Rotation :<\/span><\/b> <span class=\"citation-67 citation-end-67\">Il poss\u00e8de une rotation complexe (il \u00ab bascule \u00bb sur lui-m\u00eame en tournant en environ 30,5 heures).<\/span><\/p>\n<\/li>\n<li>\n<p data-path-to-node=\"9,2,0\"><b data-path-to-node=\"9,2,0\" data-index-in-node=\"0\"><span class=\"citation-66 citation-end-66\">Impact potentiel :<\/span><\/b> S&#8217;il venait \u00e0 percuter la Terre un jour, sa taille entra\u00eenerait des destructions consid\u00e9rables \u00e0 l&#8217;\u00e9chelle d&#8217;une r\u00e9gion enti\u00e8re, mais pas une extinction globale.<\/p>\n<p id=\"p-rc_2f36710a040e4574-37\" data-path-to-node=\"0\"><span class=\"citation-21\">L&#8217;ast\u00e9ro\u00efde <\/span><b data-path-to-node=\"0\" data-index-in-node=\"12\"><span class=\"citation-21\">(29075) 1950 DA<\/span><\/b><span class=\"citation-21\"> est un g\u00e9ocroiseur de la classe des Apollons qui mesure environ <\/span><b data-path-to-node=\"0\" data-index-in-node=\"92\"><span class=\"citation-21\">1,3 \u00e0 1,5 km de diam\u00e8tre<\/span><\/b><span class=\"citation-21 citation-end-21\">.<\/span> C&#8217;est l&#8217;un des objets spatiaux les plus \u00e9tudi\u00e9s en raison de sa trajectoire particuli\u00e8re.<\/p>\n<p id=\"p-rc_2f36710a040e4574-38\" data-path-to-node=\"1\"><span class=\"citation-20\">Sa trajectoire croise celle de la Terre, et sa taille en fait un <\/span><b data-path-to-node=\"1\" data-index-in-node=\"65\"><span class=\"citation-20\">ast\u00e9ro\u00efde potentiellement dangereux<\/span><\/b><span class=\"citation-20 citation-end-20\">.<\/span> <span class=\"citation-19 citation-end-19\">S&#8217;il devait percuter notre plan\u00e8te, les cons\u00e9quences seraient mondiales (effets majeurs sur le climat et la biosph\u00e8re).<\/span><\/p>\n<h3 id=\"p-rc_2f36710a040e4574-39\" data-path-to-node=\"2\"><span class=\"citation-18 citation-end-18\">La menace de 2880<\/span><\/h3>\n<p id=\"p-rc_2f36710a040e4574-40\" data-path-to-node=\"3\"><span class=\"citation-17\">Ce qui le rend c\u00e9l\u00e8bre, c&#8217;est la date du <\/span><b data-path-to-node=\"3\" data-index-in-node=\"41\"><span class=\"citation-17\">16 mars 2880<\/span><\/b><span class=\"citation-17 citation-end-17\">. Pendant un temps, 1950 DA d\u00e9tenait la plus forte probabilit\u00e9 connue de collision avec la Terre pour un grand ast\u00e9ro\u00efde.<\/span><\/p>\n<p id=\"p-rc_2f36710a040e4574-41\" data-path-to-node=\"4\"><span class=\"citation-16\">Les calculs r\u00e9cents de la NASA et de l&#8217;ESA ont r\u00e9\u00e9valu\u00e9 le risque : la probabilit\u00e9 d&#8217;impact est estim\u00e9e \u00e0 environ <\/span><b data-path-to-node=\"4\" data-index-in-node=\"114\"><span class=\"citation-16\">1 chance sur 50 000<\/span><\/b><span class=\"citation-16 citation-end-16\"> (soit 0,002 %).<\/span> Le risque reste donc extr\u00eamement faible, et l&#8217;\u00e9ch\u00e9ance \u00e0 tr\u00e8s long terme laisse amplement le temps d&#8217;affiner sa trajectoire ou de concevoir des missions de d\u00e9viation si cela s&#8217;av\u00e9rait n\u00e9cessaire.<\/p>\n<h3 data-path-to-node=\"5\">Caract\u00e9ristiques physiques<\/h3>\n<ul data-path-to-node=\"6\">\n<li>\n<p id=\"p-rc_2f36710a040e4574-42\" data-path-to-node=\"6,0,0\"><b data-path-to-node=\"6,0,0\" data-index-in-node=\"0\">D\u00e9couverte :<\/b> <span class=\"citation-15 citation-end-15\">Rep\u00e9r\u00e9 en 1950 par Carl A. Wirtanen, puis \u00ab perdu \u00bb de vue pendant 50 ans avant d&#8217;\u00eatre retrouv\u00e9 fin 2000.<\/span><\/p>\n<\/li>\n<li>\n<p id=\"p-rc_2f36710a040e4574-43\" data-path-to-node=\"6,1,0\"><b data-path-to-node=\"6,1,0\" data-index-in-node=\"0\"><span class=\"citation-14 citation-end-14\">Rotation rapide :<\/span><\/b> <span class=\"citation-13\">Il tourne sur lui-m\u00eame en seulement <\/span><b data-path-to-node=\"6,1,0\" data-index-in-node=\"54\"><span class=\"citation-13\">2,1 heures<\/span><\/b><span class=\"citation-13 citation-end-13\">.<\/span> \u00c0 cette vitesse, la force centrifuge est si forte que les roches \u00e0 sa surface devraient \u00eatre expuls\u00e9es. Il reste agglutin\u00e9 gr\u00e2ce \u00e0 des forces de coh\u00e9sion intermol\u00e9culaires (forces de Van der Waals).<\/p>\n<\/li>\n<li>\n<p id=\"p-rc_2f36710a040e4574-44\" data-path-to-node=\"6,2,0\"><b data-path-to-node=\"6,2,0\" data-index-in-node=\"0\">Effet Yarkovsky :<\/b> Sa trajectoire exacte sur plusieurs si\u00e8cles d\u00e9pend fortement de l&#8217;\u00e9nergie solaire qu&#8217;il absorbe et r\u00e9\u00e9met sous forme de chaleur. <span class=\"citation-12 citation-end-12\">C&#8217;est ce ph\u00e9nom\u00e8ne physique subtil qui d\u00e9placera l\u00e9g\u00e8rement son orbite au fil des si\u00e8cles.<\/span><\/p>\n<\/li>\n<\/ul>\n<p id=\"p-rc_2f36710a040e4574-45\" data-path-to-node=\"7\"><a class=\"ng-star-inserted\" href=\"https:\/\/youtu.be\/PqALSLKo8UE\" target=\"_blank\" rel=\"noopener\" data-hveid=\"0\" data-ved=\"0CAAQ_4QMahcKEwilo6TFgKGXAxUAAAAAHQAAAAAQVw\">L&#8217;AST\u00c9RO\u00cfDE qui nous rendra visite en 2029&#8230;<\/a><\/p>\n<p id=\"p-rc_2f36710a040e4574-45\" data-path-to-node=\"7\">\n<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>2004 MN4 est la d\u00e9signation provisoire de l&#8217;ast\u00e9ro\u00efde aujourd&#8217;hui officiellement nomm\u00e9 (99942) Apophis. C&#8217;est l&#8217;un&#8230;<\/p>\n","protected":false},"author":1,"featured_media":3706,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[12551,12552,39],"tags":[4636,12557,12553,4639,4641,12560,2982,2983,4649,12576,12579,12555,4654,12558,12563,12566,12565,12562,1004,12568,7314,12575,12556,5130,12570,10708,12571,12582,12559,12554,12578,12573,12564,955,12567,12574,12561,12584,4680,12572,12577,11085,12581,12580,7311,4695,12569,12583,2988,12586,12585],"class_list":["post-3705","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-12551","category-asteroide","category-espace","tag-apogee","tag-apophis","tag-asteroides","tag-astronomie","tag-atmosphere","tag-bolides","tag-ceinture-dasteroides","tag-ceinture-de-kuiper","tag-champ-magnetique","tag-chicxulub","tag-chondrites","tag-cometes","tag-cosmologie","tag-crateres","tag-deviation-dasteroide","tag-echelle-de-turin","tag-effet-yarkovsky","tag-esa","tag-espace","tag-exoplanetes","tag-exploration-spatiale","tag-extinction-massive","tag-geocroiseurs","tag-gravite","tag-hubble","tag-impact","tag-james-webb","tag-mecanique-celeste","tag-meteores","tag-meteorites","tag-meteoroides","tag-micrometeorites","tag-mission-dart","tag-nasa","tag-nuage-de-oort","tag-onde-de-choc","tag-orbites","tag-pericentre","tag-perigee","tag-poussiere-spatiale","tag-regolithe","tag-rentree-atmospherique","tag-roches-spatiales","tag-siderites","tag-sondes-spatiales","tag-systeme-solaire","tag-telescope-spatial","tag-trajectoire","tag-vent-solaire","tag-vol-spatial","tag-zero-gravite"],"jetpack_publicize_connections":[],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"https:\/\/www.laurensoff.com\/wordpress\/wp-content\/uploads\/2026\/10\/1200x768_vue-artiste-asteroides-passant-pres-terre-e1791139198332.jpg","_links":{"self":[{"href":"https:\/\/www.laurensoff.com\/wordpress\/wp-json\/wp\/v2\/posts\/3705","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.laurensoff.com\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.laurensoff.com\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.laurensoff.com\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.laurensoff.com\/wordpress\/wp-json\/wp\/v2\/comments?post=3705"}],"version-history":[{"count":1,"href":"https:\/\/www.laurensoff.com\/wordpress\/wp-json\/wp\/v2\/posts\/3705\/revisions"}],"predecessor-version":[{"id":3707,"href":"https:\/\/www.laurensoff.com\/wordpress\/wp-json\/wp\/v2\/posts\/3705\/revisions\/3707"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.laurensoff.com\/wordpress\/wp-json\/wp\/v2\/media\/3706"}],"wp:attachment":[{"href":"https:\/\/www.laurensoff.com\/wordpress\/wp-json\/wp\/v2\/media?parent=3705"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.laurensoff.com\/wordpress\/wp-json\/wp\/v2\/categories?post=3705"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.laurensoff.com\/wordpress\/wp-json\/wp\/v2\/tags?post=3705"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}