{"id":589,"date":"2004-11-15T13:56:00","date_gmt":"2004-11-15T12:56:00","guid":{"rendered":"https:\/\/kids.esa.int\/the_big_bang\/"},"modified":"2026-10-08T00:29:59","modified_gmt":"2026-10-07T22:29:59","slug":"the_big_bang","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/fr\/the_big_bang\/","title":{"rendered":"Le Big Bang"},"content":{"rendered":"
\n

La plupart des astronomes croient que l'Univers a commenc\u00e9 par un Big Bang (une Grande Explosion) il y a environ 14 milliards d'ann\u00e9es. A cette \u00e9poque, l'Univers se trouvait \u00e0 l'int\u00e9rieur d'une bulle des milliers de fois plus petite qu'une t\u00eate d'\u00e9pingle. Elle \u00e9tait plus chaude et plus dense que tout ce que nous pouvons imaginer.<\/p>\n<\/div>\n

Puis elle explosa brusquement. L'Univers tel que nous le connaissons \u00e9tait n\u00e9. Le temps, l'espace et la mati\u00e8re naquirent tous avec le Big Bang. En une fraction de seconde, l'Univers, qui \u00e9tait plus petit qu'un simple atome, devint plus grand qu'une galaxie. Et il continua \u00e0 grandir \u00e0 une vitesse incroyable. Il grandit encore aujourd'hui.<\/p>\n

Au fur et \u00e0 mesure que l'Univers s'agrandissait et se refroidissait, l'\u00e9nergie se transformait en particules de mati\u00e8re et d'antimati\u00e8re. Ces deux types oppos\u00e9s de particules se d\u00e9truisirent presque enti\u00e8rement. Mais un peu de mati\u00e8re surv\u00e9cut. Des particules plus stables, appel\u00e9es protons et neutrons, commenc\u00e8rent \u00e0 se former alors que l'Univers n'\u00e9tait n\u00e9 que depuis une seconde.<\/p>\n

Au cours des trois minutes suivantes, la temp\u00e9rature chuta au-dessous de 1 milliard de degr\u00e9s Celsius. Il faisait donc assez 'froid' pour que les protons et les neutrons se r\u00e9unissent pour former des noyaux d'hydrog\u00e8ne et d'h\u00e9lium.<\/p>\n

300.000 ans plus tard, la temp\u00e9rature de l'Univers \u00e9tait tomb\u00e9e \u00e0 environ 3.000\u00b0C. Les noyaux atomiques purent enfin capturer des \u00e9lectrons et former des atomes. L'Univers se remplit de nuages d'hydrog\u00e8ne et d'h\u00e9lium.<\/p>","protected":false},"excerpt":{"rendered":"

Most astronomers believe the Universe began in a Big Bang about 14 billion years ago. At that time, the entire Universe was inside a bubble that was thousands of times […]<\/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\/2014\/06\/nearby_galaxy\/17883658-2-eng-GB\/Nearby_galaxy.jpg","esa_banner_description":"","esa_banner_credit":"ESA","esa_banner_licence":"ESA Standard Licence","esa_banner_detail_url":"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2014\/06\/Nearby_galaxy","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":[10,11,19],"tags":[2],"panel":[],"language":[],"age":[],"duration":[],"resource_type":[],"audience":[],"wf_post_folders":[],"class_list":["post-589","post","type-post","status-publish","format-standard","hentry","category-learn","category-our-universe","category-story-of-the-universe","tag-background-article"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/589","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=589"}],"version-history":[{"count":1,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/589\/revisions"}],"predecessor-version":[{"id":1732,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/589\/revisions\/1732"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/media?parent=589"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/categories?post=589"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/tags?post=589"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/panel?post=589"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/language?post=589"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/age?post=589"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/duration?post=589"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/resource_type?post=589"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/audience?post=589"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/wf_post_folders?post=589"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}