{"id":220673,"date":"2025-07-02T12:38:10","date_gmt":"2025-07-02T12:38:10","guid":{"rendered":"https:\/\/www.europesays.com\/fr\/220673\/"},"modified":"2025-07-02T12:38:10","modified_gmt":"2025-07-02T12:38:10","slug":"le-mysterieux-signal-radio-provenait-dun-satellite-pourtant-inactif-depuis-58-ans","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/fr\/220673\/","title":{"rendered":"Le myst\u00e9rieux signal radio provenait d\u2019un satellite pourtant inactif depuis 58 ans"},"content":{"rendered":"<p>Des <a href=\"https:\/\/www.20minutes.fr\/sciences\/astronomie\/\" class=\"color-ultramarine c-link\" target=\"_blank\" rel=\"noopener\">astronomes <\/a>australiens avaient capt\u00e9 en juin\u00a02024, \u00e0 l\u2019aide du radiot\u00e9lescope ASKAP, un signal <a href=\"https:\/\/www.20minutes.fr\/dossier\/radio\" class=\"color-ultramarine c-link\" target=\"_blank\" rel=\"noopener\">radio <\/a>semblable \u00e0 un flash extr\u00eamement puissant. Les scientifiques estimaient \u00e0 l\u2019origine qu\u2019il pouvait s\u2019agir d\u2019un sursaut radio rapide, un ph\u00e9nom\u00e8ne encore inexpliqu\u00e9 et potentiellement li\u00e9 aux magn\u00e9tars. La v\u00e9ritable explication de ce flash radio, pr\u00e9sent\u00e9e lundi dans <a href=\"https:\/\/arxiv.org\/abs\/2506.11462\" rel=\"nofollow noopener\" target=\"_blank\" class=\"color-ultramarine c-link\">The Astrophysical Journal Letters<\/a>, s\u2019av\u00e8re bien plus d\u00e9cevante, comme le rapporte <a href=\"https:\/\/edition.cnn.com\/2025\/06\/30\/science\/satellite-strange-radio-signal-relay-2\" rel=\"nofollow noopener\" target=\"_blank\" class=\"color-ultramarine c-link\">CNN<\/a>.<\/p>\n<p>Un coupable tr\u00e8s proche<\/p>\n<p>En effet, pour d\u00e9couvrir la source de ce signal, les chercheurs n\u2019ont pas d\u00fb aller voir du c\u00f4t\u00e9 des <a href=\"https:\/\/www.20minutes.fr\/dossier\/galaxie\" class=\"color-ultramarine c-link\" target=\"_blank\" rel=\"noopener\">galaxies <\/a>lointaines et des magn\u00e9tars. Le flash avait \u00e9t\u00e9 \u00e9mis \u00e0 moins de 4.500\u00a0km de distance de la Terre, soit depuis son orbite moyenne.<\/p>\n<p>Les scientifiques ont ainsi rapidement identifi\u00e9 le coupable\u00a0: l\u2019ancien <a href=\"https:\/\/www.20minutes.fr\/sciences\/satellite\/\" class=\"color-ultramarine c-link\" target=\"_blank\" rel=\"noopener\">satellite <\/a>Relay 2. Lanc\u00e9 par la <a href=\"https:\/\/www.20minutes.fr\/sciences\/nasa\/\" class=\"color-ultramarine c-link\" target=\"_blank\" rel=\"noopener\">NASA<\/a> en\u00a01964, ce dispositif exp\u00e9rimental de communication a \u00e9t\u00e9 utilis\u00e9 pour retransmettre les Jeux olympiques de Tokyo de\u00a01964\u00a0aux \u00c9tats-Unis et en <a href=\"https:\/\/www.20minutes.fr\/dossier\/europe\" class=\"color-ultramarine c-link\" target=\"_blank\" rel=\"noopener\">Europe<\/a>. Il a cependant cess\u00e9 de fonctionner en\u00a01967, devenant avec son compagnon Relay 1 l\u2019un des nombreux d\u00e9bris qui orbitent autour de la <a href=\"https:\/\/www.20minutes.fr\/sciences\/terre\/\" class=\"color-ultramarine c-link\" target=\"_blank\" rel=\"noopener\">Terre<\/a>.<\/p>\n<p>\u00c9lectricit\u00e9 statique ou\u00a0microm\u00e9t\u00e9orite\u00a0?<\/p>\n<p>Mais alors, comment expliquer qu\u2019un satellite que l\u2019on pensait mort soit capable d\u2019\u00e9mettre un tel signal radio, m\u00eame pendant quelques nanosecondes\u00a0? Plusieurs hypoth\u00e8ses ont \u00e9t\u00e9 avanc\u00e9es. Tout d\u2019abord, une accumulation d\u2019\u00e9lectricit\u00e9 statique sur la coque m\u00e9tallique du satellite. Cette accumulation d\u2019\u00e9lectrons aurait provoqu\u00e9 un court-circuit qui aurait \u00e0 son tour entra\u00een\u00e9 l\u2019\u00e9tincelle responsable du signal.<\/p>\n<\/p>\n<p>De fa\u00e7on moins probable, les chercheurs ont \u00e9galement envisag\u00e9 l\u2019hypoth\u00e8se d\u2019un impact avec une microm\u00e9t\u00e9orite qui aurait transform\u00e9 les d\u00e9bris en plasma, lib\u00e9rant une importante quantit\u00e9 d\u2019\u00e9nergie. Dans tous les cas, ces r\u00e9sultats rappellent que les nombreux d\u00e9bris spatiaux peuvent interf\u00e9rer avec les observations galactiques.<\/p>\n","protected":false},"excerpt":{"rendered":"Des astronomes australiens avaient capt\u00e9 en juin\u00a02024, \u00e0 l\u2019aide du radiot\u00e9lescope ASKAP, un signal radio semblable \u00e0 un&hellip;\n","protected":false},"author":2,"featured_media":220674,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[5035,386,1011,27,142,333,4313,43,40,41,39,42,44],"class_list":{"0":"post-220673","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-sciences-et-technologies","8":"tag-australie","9":"tag-espace","10":"tag-fr","11":"tag-france","12":"tag-high-tech","13":"tag-nasa","14":"tag-satellite","15":"tag-science","16":"tag-science-and-technology","17":"tag-sciences","18":"tag-sciences-et-technologies","19":"tag-technologies","20":"tag-technology"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@fr\/114783682909228706","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/fr\/wp-json\/wp\/v2\/posts\/220673","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/fr\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/fr\/wp-json\/wp\/v2\/comments?post=220673"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/fr\/wp-json\/wp\/v2\/posts\/220673\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/fr\/wp-json\/wp\/v2\/media\/220674"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/fr\/wp-json\/wp\/v2\/media?parent=220673"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/fr\/wp-json\/wp\/v2\/categories?post=220673"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/fr\/wp-json\/wp\/v2\/tags?post=220673"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}