{"id":1130,"date":"2004-11-15T15:52:00","date_gmt":"2004-11-15T14:52:00","guid":{"rendered":"https:\/\/kids.esa.int\/threats_from_space\/"},"modified":"2026-10-08T00:36:20","modified_gmt":"2026-10-07T22:36:20","slug":"threats_from_space","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/fr\/threats_from_space\/","title":{"rendered":"Menaces venues de l'espace"},"content":{"rendered":"<div class=\"lede\">\n<p>La Terre est la plus grande des quatre plan\u00e8tes rocheuses de notre syst\u00e8me solaire. Elle est tr\u00e8s lourde par rapport \u00e0 sa taille. En son centre se trouve un grand noyau riche en fer, o\u00f9 la temp\u00e9rature atteint 6 000 degr\u00e9s Celsius, soit une chaleur \u00e9quivalente \u00e0 celle de la surface du Soleil.<\/p>\n<\/div>\n<p>Le noyau externe liquide tourbillonne au rythme de la rotation de la plan\u00e8te, agissant comme une dynamo de v\u00e9lo. Cette dynamo fait que la Terre se comporte comme un puissant aimant.<\/p>\n<p>En formant une bulle invisible autour de la plan\u00e8te, le champ magn\u00e9tique terrestre agit comme un bouclier. Il prot\u00e8ge ainsi la Terre de la plupart des particules \u00e0 grande vitesse projet\u00e9es dans l'espace par les temp\u00eates solaires. Il arrive parfois que des particules franchissent cette barri\u00e8re \u00e0 proximit\u00e9 des p\u00f4les magn\u00e9tiques. C'est ce qui donne naissance aux aurores terrestres, commun\u00e9ment appel\u00e9es \u00ab aurores bor\u00e9ales \u00bb et \u00ab aurores australes \u00bb.<\/p>\n<p>La surface de la Terre est \u00e9galement prot\u00e9g\u00e9e par une atmosph\u00e8re \u00e9paisse. Celle-ci bloque la majeure partie des rayonnements nocifs provenant de l'espace. Elle provoque \u00e9galement la combustion des petits objets qui p\u00e9n\u00e8trent dans l'atmosph\u00e8re, sous forme d'\u00e9toiles filantes. Seuls les m\u00e9t\u00e9orites et les com\u00e8tes de grande taille atteignent la surface et explosent, laissant derri\u00e8re eux de grands crat\u00e8res.<\/p>\n<p>Contrairement \u00e0 la Lune et aux autres plan\u00e8tes rocheuses, la Terre compte aujourd\u2019hui peu de crat\u00e8res d\u2019impact. La plupart d\u2019entre eux ont \u00e9t\u00e9 \u00e9rod\u00e9s ou combl\u00e9s par l\u2019action de l\u2019eau courante, du vent et de la glace.<\/p>","protected":false},"excerpt":{"rendered":"<p>Earth is the largest of the four rocky planets in our Solar System. It is very heavy for its size. At its centre is a large, iron-rich core, where the [&hellip;]<\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"closed","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,"esa_banner_image":"https:\/\/www.esa.int\/var\/esa\/storage\/images\/esa_multimedia\/images\/2004\/05\/meteor_crater_in_arizona3\/17895645-2-eng-GB\/Meteor_Crater_in_Arizona.jpg","esa_banner_description":"Meteor Crater in Arizona","esa_banner_credit":"David Roddy, USGS","esa_banner_licence":"No ESA licences available","esa_banner_detail_url":"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2004\/05\/Meteor_Crater_in_Arizona3","esa_external_url":"","esa_external_new_window":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_post_was_ever_published":true},"categories":[10,11,12],"tags":[2],"panel":[],"language":[],"age":[],"duration":[],"resource_type":[],"audience":[],"wf_post_folders":[],"class_list":["post-1130","post","type-post","status-publish","format-standard","hentry","category-learn","category-our-universe","category-planets-and-moons","tag-background-article"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/1130","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/comments?post=1130"}],"version-history":[{"count":1,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/1130\/revisions"}],"predecessor-version":[{"id":2273,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/1130\/revisions\/2273"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/media?parent=1130"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/categories?post=1130"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/tags?post=1130"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/panel?post=1130"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/language?post=1130"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/age?post=1130"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/duration?post=1130"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/resource_type?post=1130"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/audience?post=1130"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/wf_post_folders?post=1130"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}