{"id":181,"date":"2021-12-02T12:51:04","date_gmt":"2021-12-02T11:51:04","guid":{"rendered":"https:\/\/kids.esa.int\/spacecraft_astronomers_use_esa_space_telescope_to_find_missing_matter\/"},"modified":"2026-10-08T00:25:12","modified_gmt":"2026-10-07T22:25:12","slug":"spacecraft_astronomers_use_esa_space_telescope_to_find_missing_matter","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/fr\/spacecraft_astronomers_use_esa_space_telescope_to_find_missing_matter\/","title":{"rendered":"Des astronomes utilisent un t\u00e9lescope spatial de l'ESA pour trouver de la mati\u00e8re manquante"},"content":{"rendered":"<div class=\"lede\">\n<p>Dans l\u2019espace, tout ce que nous voyons - qu\u2019il s\u2019agisse d\u2019\u00e9toiles, de plan\u00e8tes ou d\u2019astronautes - est compos\u00e9 d\u2019un type de mati\u00e8re que nous appelons les baryons. Une importante quantit\u00e9 de mati\u00e8re baryonique semble cependant manquer dans l\u2019univers, et nous \u00e9prouvons des difficult\u00e9s \u00e0 la retrouver. Un groupe d\u2019astronomes a utilis\u00e9 le t\u00e9lescope spatial XMM-Newton de l\u2019ESA pour nous aider \u00e0 r\u00e9soudre ce myst\u00e8re cosmique!<\/p>\n<\/div>\n<p>Nous pouvons estimer le nombre de baryons que comporte l\u2019Univers en \u00e9tudiant un ph\u00e9nom\u00e8ne appel\u00e9 le fond diffus cosmologique, un ancien type de rayonnement \u00e9mis 380 000 ans seulement apr\u00e8s le Big Bang. Les baryons poss\u00e8dent une dur\u00e9e de vie estim\u00e9e de plusieurs milliards d\u2019ann\u00e9es, mais environ la moiti\u00e9 de cette mati\u00e8re semble manquer dans notre Univers.<\/p>\n<figure class=\"wp-block-image size-large\" data-width=\"700\" data-credit=\"ESA\" data-detail-url=\"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2018\/07\/Spider_senses2\" 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\" loading=\"lazy\" style=\"max-width:100%;height:auto\" src=\"https:\/\/www.esa.int\/var\/esa\/storage\/images\/esa_multimedia\/images\/2018\/07\/spider_senses2\/17900532-2-eng-GB\/Spider_senses.jpg\" alt=\"Spider senses\"><figcaption>Le sixi\u00e8me sens<\/figcaption><\/figure>\n<p>Fabrizio Nicastro est l\u2019un des scientifiques qui cherche \u00e0 r\u00e9soudre cette \u00e9nigme. Selon lui : \u00ab Les baryons manquants repr\u00e9sentent l\u2019un des plus grands myst\u00e8res de l\u2019astrophysique moderne. Nous savons que cette mati\u00e8re est cens\u00e9e \u00eatre l\u00e0, nous la voyons m\u00eame dans l\u2019Univers primitif, mais nous ne parvenons pas \u00e0 la saisir. O\u00f9 est-elle pass\u00e9e ? \u00bb<\/p>\n<p>M\u00eame en additionnant toutes les \u00e9toiles et tout le gaz pr\u00e9sents dans l\u2019espace, ainsi que tout ce que les astronomes ont pu d\u00e9tecter, il manquait encore 40% de baryons. Ils savent vraiment bien se cacher ! Fabrizio et ses amis ont d\u00e9cid\u00e9 d\u2019utiliser un t\u00e9lescope sp\u00e9cial pour les aider dans leurs recherches : le XMM-Newton de l\u2019ESA. Ce t\u00e9lescope se trouve dans l\u2019espace et observe les rayons X plut\u00f4t que la lumi\u00e8re visible que nos yeux per\u00e7oivent.<\/p>\n<p>Ces astronomes intr\u00e9pides ont utilis\u00e9 XMM-Newton pour observer un quasar, c'est-\u00e0-dire une galaxie massive abritant en son centre un trou noir supermassif qui aspire de la mati\u00e8re et \u00e9met d'\u00e9normes quantit\u00e9s de rayons X ! En \u00e9tudiant attentivement les donn\u00e9es, ils ont d\u00e9couvert des traces d'oxyg\u00e8ne cach\u00e9es dans l'espace entre nous et le quasar. Nous n\u2019avions jamais pu observer cela auparavant ! Fabrizio explique : \u201c Il existe d\u2019\u00e9normes r\u00e9serves de mati\u00e8re \u2013 dont de l\u2019oxyg\u00e8ne \u2013 qui s\u2019y trouvent, et ce exactement dans les quantit\u00e9s auxquelles nous nous attendions ; nous pouvons donc enfin combler le d\u00e9ficit du bilan baryonique de l\u2019Univers. \u201d<\/p>\n<figure class=\"wp-block-image size-large\" data-width=\"5945\" data-credit=\"Illustrations and composition: ESA \/ ATG medialab; data: ESA \/ XMM-Newton \/ F. Nicastro et al. 2018; cosmological simulation: R. Cen\" data-detail-url=\"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2018\/07\/Detecting_the_warm-hot_intergalactic_medium\" 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\" loading=\"lazy\" style=\"max-width:100%;height:auto\" src=\"https:\/\/www.esa.int\/var\/esa\/storage\/images\/esa_multimedia\/images\/2018\/07\/detecting_the_warm-hot_intergalactic_medium\/17892168-2-eng-GB\/Detecting_the_warm-hot_intergalactic_medium.jpg\" alt=\"Detecting the warm-hot intergalactic medium\"><figcaption>D\u00e9tection du milieu intergalactique ti\u00e8de \u00e0 chaud<\/figcaption><\/figure>\n<p>Les baryons manquants se cachaient dans une zone de brume intergalactique chaude \u00e9tendue sur des centaines de milliers d\u2019ann\u00e9es-lumi\u00e8re entre les galaxies. Le myst\u00e8re a \u00e9t\u00e9 r\u00e9solu, et les astronomes peuvent aujourd\u2019hui commencer \u00e0 \u00e9tudier ces baryons afin d\u2019approfondir nos connaissances !<\/p>\n<p><b>Fait int\u00e9ressant :<\/b> Bien que la mati\u00e8re baryonique constitue tout ce que nous voyons, elle ne repr\u00e9sente que 5% de la mati\u00e8re pr\u00e9sente dans l'Univers ! La myst\u00e9rieuse mati\u00e8re noire repr\u00e9sente environ 25%, et l'\u00e9nergie noire environ 70%.<\/p>","protected":false},"excerpt":{"rendered":"<p>Everything we see in space, such as stars, planets and even people, is made from a type of matter called baryons. However, a lot of the baryons in the Universe [&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\/2018\/07\/xmm-newton\/17910751-2-eng-GB\/XMM-Newton.jpg","esa_banner_description":"XMM-Newton","esa_banner_credit":"ESA-C. Carreau","esa_banner_licence":"ESA Standard Licence","esa_banner_detail_url":"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2018\/07\/XMM-Newton","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-181","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\/181","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=181"}],"version-history":[{"count":4,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/181\/revisions"}],"predecessor-version":[{"id":4345,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/181\/revisions\/4345"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/media?parent=181"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/categories?post=181"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/tags?post=181"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/panel?post=181"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/language?post=181"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/age?post=181"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/duration?post=181"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/resource_type?post=181"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/audience?post=181"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/wf_post_folders?post=181"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}