{"id":439,"date":"2017-06-21T12:26:00","date_gmt":"2017-06-21T10:26:00","guid":{"rendered":"https:\/\/kids.esa.int\/evidence_found_that_comets_helped_to_make_earth_s_atmosphere\/"},"modified":"2026-10-08T00:28:13","modified_gmt":"2026-10-07T22:28:13","slug":"evidence_found_that_comets_helped_to_make_earth_s_atmosphere","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/fr\/evidence_found_that_comets_helped_to_make_earth_s_atmosphere\/","title":{"rendered":"Des com\u00e8tes ont contribu\u00e9 \u00e0 fa\u00e7onner l\u2019atmosph\u00e8re de la Terre !"},"content":{"rendered":"<div class=\"lede\">\n<p>En 2016, une sonde de l'ESA baptis\u00e9e Rosetta a men\u00e9 \u00e0 bien une mission extraordinaire : se rendre jusqu'\u00e0 une com\u00e8te, l'\u00e9tudier depuis son orbite et y envoyer un atterrisseur robotis\u00e9 ! Les scientifiques ont ainsi d\u00e9couvert des preuves indiquant que des com\u00e8tes se sont \u00e9cras\u00e9es sur la Terre il y a tr\u00e8s longtemps et ont contribu\u00e9 \u00e0 la formation de notre atmosph\u00e8re !<\/p>\n<\/div>\n<p>Pour faire cette d\u00e9couverte historique, les chercheurs ont agi comme des d\u00e9tectives. Nous savons que l\u2019atmosph\u00e8re de la Terre contient de petites quantit\u00e9s d\u2019un gaz appel\u00e9 X\u00e9non. Notre atmosph\u00e8re contient plusieurs vari\u00e9t\u00e9s de x\u00e9non, chacune \u00e9tant constitu\u00e9e de mani\u00e8re sensiblement diff\u00e9rente. Cette sorte de signature nous permet d\u2019identifier les diff\u00e9rentes vari\u00e9t\u00e9s de ce gaz.<\/p>\n<figure class=\"wp-block-image size-large\" data-width=\"1843\" data-credit=\"ESA\" data-detail-url=\"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2017\/06\/Comet_67_PChuryumov-Gerasimenko_on_15_May_2016\" data-licence=\"ESA Standard Licence\" data-licence-url=\"https:\/\/www.esa.int\/ESA_Multimedia\/Terms_and_conditions_of_use_of_images_and_videos_available_on_the_esa_website\"><img decoding=\"async\" style=\"max-width: 100%; height: auto;\" src=\"https:\/\/www.esa.int\/var\/esa\/storage\/images\/esa_multimedia\/images\/2017\/06\/comet_67_pchuryumov-gerasimenko_on_15_may_2016\/17905867-2-eng-GB\/Comet_67_PChuryumov-Gerasimenko_on_15_May_2016.jpg\" alt=\"A close-up photo of the comet\" \/><figcaption>Une photo en gros plan de la com\u00e8te<\/figcaption><\/figure>\n<p>Nos \u00e9quipes scientifiques ont d\u00e9j\u00e0 trouv\u00e9 du x\u00e9non dans la fine atmosph\u00e8re martienne, dans les ast\u00e9ro\u00efdes, sur Jupiter ou encore dans des particules provenant du Soleil. Mais, sur Terre, le x\u00e9non poss\u00e8de une signature diff\u00e9rente ! Cela signifie que le x\u00e9non de notre plan\u00e8te doit provenir d\u2019un autre endroit que le x\u00e9non que l\u2019on trouve dans notre syst\u00e8me solaire.<\/p>\n<p>Le x\u00e9non de la Terre est tr\u00e8s ancien. Avec le temps, sa composition a chang\u00e9. Les scientifiques ont utilis\u00e9 des mod\u00e8les informatiques pour simuler la nature du x\u00e9non terrien il y a quatre milliards et demi d\u2019ann\u00e9es, lors de la formation de notre plan\u00e8te. C\u2019est l\u00e0 que la sonde spatiale Rosetta entre en sc\u00e8ne... Savez-vous ce que Rosetta a d\u00e9couvert, en \u00e9tudiant sa com\u00e8te ? Que le x\u00e9non qui s\u2019y trouvait poss\u00e9dait la m\u00eame signature que l\u2019ancien x\u00e9non de la Terre !<\/p>\n<figure class=\"wp-block-image size-large\" data-width=\"1920\" data-credit=\"ESA\" data-detail-url=\"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2017\/06\/Fresh_from_Earth\" data-licence=\"ESA Standard Licence\" data-licence-url=\"https:\/\/www.esa.int\/ESA_Multimedia\/Terms_and_conditions_of_use_of_images_and_videos_available_on_the_esa_website\"><img decoding=\"async\" style=\"max-width: 100%; height: auto;\" src=\"https:\/\/www.esa.int\/var\/esa\/storage\/images\/esa_multimedia\/images\/2017\/06\/fresh_from_earth\/17898569-2-eng-GB\/Fresh_from_Earth.jpg\" alt=\"Comets could have helped to make Earth\u2019s atmosphere, billions of years ago\" \/><figcaption>Il y a des milliards d'ann\u00e9es, les com\u00e8tes auraient pu contribuer \u00e0 la formation de l'atmosph\u00e8re terrestre.<\/figcaption><\/figure>\n<p>Cette d\u00e9couverte prouve que, il y a longtemps de cela, des com\u00e8tes ont percut\u00e9 notre Terre en \u00e9tant charg\u00e9es de x\u00e9non. Cependant, m\u00eame si le x\u00e9non de la com\u00e8te est similaire \u00e0 celui de notre ancienne Terre, il n\u2019est pas exactement identique. Plus pr\u00e9cis\u00e9ment, les donn\u00e9es collect\u00e9es par Rosetta d\u00e9montrent que les com\u00e8tes ont apport\u00e9 environ 22 % du x\u00e9non originel de notre plan\u00e8te, le reste provenant probablement d\u2019ast\u00e9ro\u00efdes.<\/p>\n<p>Si les com\u00e8tes ont d\u00e9pos\u00e9 du x\u00e9non sur notre plan\u00e8te, pourraient-elles avoir apport\u00e9 autre chose ? Elles transportaient peut-\u00eatre \u00e9galement des acides amin\u00e9s, l\u2019un des ingr\u00e9dients essentiels \u00e0 la vie !<\/p>\n<figure class=\"wp-block-image size-large\" data-width=\"1920\" data-credit=\"ESA\" data-detail-url=\"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2017\/06\/Rosetta_goes_on_an_excursion\" data-licence=\"ESA Standard Licence\" data-licence-url=\"https:\/\/www.esa.int\/ESA_Multimedia\/Terms_and_conditions_of_use_of_images_and_videos_available_on_the_esa_website\"><img decoding=\"async\" style=\"max-width: 100%; height: auto;\" src=\"https:\/\/www.esa.int\/var\/esa\/storage\/images\/esa_multimedia\/images\/2017\/06\/rosetta_goes_on_an_excursion\/17866860-3-eng-GB\/Rosetta_goes_on_an_excursion.png\" alt=\"Have you seen our cartoons about Rosetta?\" \/><figcaption>Avez-vous vu nos bandes dessin\u00e9es sur Rosetta ?<\/figcaption><\/figure>\n<p>Gr\u00e2ce aux donn\u00e9es renvoy\u00e9es par la sonde Rosetta de l\u2019ESA, nous allons un jour pouvoir r\u00e9pondre \u00e0 ces questions... et \u00e0 bien d\u2019autres encore !<\/p>\n<p><b>Fait int\u00e9ressant :<\/b> Le nom officiel de la com\u00e8te \u00e9tudi\u00e9e par Rosetta est 67P\/Churyumov-Gerasimenko. Rosetta s'est approch\u00e9e \u00e0 une distance incroyablement proche de la com\u00e8te pour pr\u00e9lever du x\u00e9non : \u00e0 seulement 5 km au-dessus de sa surface !<\/p>","protected":false},"excerpt":{"rendered":"<p>In 2016, an ESA probe called Rosetta completed an incredible mission: flying to a comet, studying it from orbit, and sending down a robotic lander! They then found evidence that [&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\/2017\/06\/rosetta_at_comet\/17873224-2-eng-GB\/Rosetta_at_Comet.jpg","esa_banner_description":"Rosetta and its lander have made amazing discoveries","esa_banner_credit":"ESA","esa_banner_licence":"ESA Standard Licence","esa_banner_detail_url":"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2017\/06\/Rosetta_at_Comet","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":[26],"tags":[],"panel":[],"language":[],"age":[],"duration":[],"resource_type":[],"audience":[],"wf_post_folders":[],"class_list":["post-439","post","type-post","status-publish","format-standard","hentry","category-news"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/439","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=439"}],"version-history":[{"count":5,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/439\/revisions"}],"predecessor-version":[{"id":4475,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/439\/revisions\/4475"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/media?parent=439"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/categories?post=439"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/tags?post=439"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/panel?post=439"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/language?post=439"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/age?post=439"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/duration?post=439"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/resource_type?post=439"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/audience?post=439"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/wf_post_folders?post=439"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}