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Cette animation montre comment la Terre et la Lune se déplaceront ces trois prochaines années

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Le barycentre de la Lune n'est pas exactement aligné sur le centre de la Terre. © Insider
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{"blocks":[{"key":"aev3d","text":"La Lune tourne autour de la Terre, n'est-ce pas ? La réponse est en fait un peu plus compliquée que cela. La Lune tourne autour d'un point situé à environ 5 000 km du centre de notre planète, juste sous sa surface. La Terre oscille autour de ce point, elle aussi, en faisant ses propres cercles. Ce point est le centre de masse du système Terre-Lune, connu comme le barycentre. C'est le point d'un objet (ou d'un système d'objets) où il peut être parfaitement équilibré, la masse étant répartie uniformément sur tous les côtés.","type":"unstyled","depth":0,"inlineStyleRanges":[],"entityRanges":[],"data":{}},{"key":"22fsp","text":"Le barycentre de la lune terrestre n'est pas exactement aligné sur le centre de notre planète. Au contraire, il se trouve \"toujours juste en dessous de la surface de la Terre\", comme l'a expliqué sur Twitter James O'Donoghue, un spécialiste des sciences planétaires de l'agence spatiale japonaise (JAXA). Il est difficile d'imaginer à quoi cela ressemble sans le voir par soi-même. James O'Donoghue a donc créé une animation pour montrer ce qui se passe. Elle montre comment la Terre et la Lune vont se déplacer au cours des trois prochaines années.","type":"unstyled","depth":0,"inlineStyleRanges":[],"entityRanges":[{"offset":200,"length":7,"key":0},{"offset":411,"length":13,"key":1}],"data":{}},{"key":"k623","text":"À lire aussi — Cette simple animation montre de quoi est constituée la croûte terrestre","type":"unstyled","depth":0,"inlineStyleRanges":[{"offset":0,"length":87,"style":"BOLD"},{"offset":0,"length":87,"style":"ITALIC"}],"entityRanges":[{"offset":15,"length":72,"key":2}],"data":{}},{"key":"2fmlk","text":"","type":"atomic","depth":0,"inlineStyleRanges":[],"entityRanges":[],"data":{"type":"media","key":"2fmlk","caption":null,"format":null,"iframely":{"meta":{"media":"player","site":"YouTube","author":"Dr James O'Donoghue","views":"278291","date":"2020-05-01T08:46:33.000Z","dislikes":"6","canonical":"https://www.youtube.com/watch?v=7hMfCCqSdFc","duration":48,"title":"The Earth-Moon Barycenter: The Moon doesn't orbit Earth's center and Earth doesn't stay still (3D!)","author_url":"https://www.youtube.com/channel/UCSaCQr2ppyNUY_kjnWY1yVQ","likes":"344","description":"Earth moves up to 5000 km away from the common center of mass (barycenter) between Earth and Moon, this is due to the Moon's gravitational influence! So here *both* Earth & Moon orbit their common center of mass (and do stick around to see the speed-up on Aug 12...). Made with actual predictive data from NASA\nFollow for early releases and Q&A @physicsJ Twitter"},"links":{"player":[{"href":"https://www.youtube.com/embed/7hMfCCqSdFc?rel=0&showinfo=1","rel":["player","html5","accelerometer","clipboard-write","encrypted-media","gyroscope","picture-in-picture","ssl"],"type":"text/html","options":{"_start":{"label":"Start from","value":"","placeholder":"ex.: 11, 1m10s"},"_end":{"label":"End on","value":"","placeholder":"ex.: 11, 1m10s"}},"media":{"aspect-ratio":1.7777777777777777,"scrolling":"no"},"html":"

"},{"href":"https://www.youtube.com/embed/7hMfCCqSdFc?rel=0&showinfo=1&autoplay=1","rel":["player","html5","accelerometer","clipboard-write","encrypted-media","gyroscope","picture-in-picture","ssl","autoplay"],"type":"text/html","options":{"_start":{"label":"Start from","value":"","placeholder":"ex.: 11, 1m10s"},"_end":{"label":"End on","value":"","placeholder":"ex.: 11, 1m10s"}},"media":{"aspect-ratio":1.7777777777777777,"scrolling":"no"},"html":"

"}],"thumbnail":[{"href":"https://i.ytimg.com/vi/7hMfCCqSdFc/maxresdefault.jpg","rel":["thumbnail","ssl"],"type":"image/jpeg","media":{"width":1280,"height":720}},{"href":"https://i.ytimg.com/vi/7hMfCCqSdFc/mqdefault.jpg","rel":["thumbnail","ssl"],"type":"image/jpeg","media":{"width":320,"height":180}}],"icon":[{"href":"//www.google.com/favicon.ico","rel":["shortcut","icon","ssl"],"type":"image/icon"}]},"rel":["player","html5","accelerometer","clipboard-write","encrypted-media","gyroscope","picture-in-picture","ssl"],"html":"

","options":{"_start":{"label":"Start from","value":"","placeholder":"ex.: 11, 1m10s"},"_end":{"label":"End on","value":"","placeholder":"ex.: 11, 1m10s"}}},"focusPoint":{"x":null,"y":null,"relativeX":null,"relativeY":null},"target":null,"rel":null}},{"key":"c3m3m","text":"La distance entre la Terre et la Lune n'est pas à l'échelle dans l'animation, mais James O'Donoghue a utilisé les données de la NASA, de sorte que les positions dans le temps sont précises. \"Vous pouvez interrompre l'animation à la date actuelle pour savoir où se trouvent physiquement la Terre et la Lune en ce moment\", a déclaré le spécialiste des sciences planétaires.","type":"unstyled","depth":0,"inlineStyleRanges":[],"entityRanges":[],"data":{}},{"key":"9cfv9","text":"Les barycentres au coeur des systèmes planétaires","type":"header-two","depth":0,"inlineStyleRanges":[],"entityRanges":[],"data":{}},{"key":"emosg","text":"Chaque système planétaire — y compris l'étoile ou la planète qui semble être au centre — tourne autour d'un point invisible comme celui-ci. Le barycentre de notre système solaire se trouve parfois à l'intérieur du soleil, parfois à l'extérieur. Les barycentres peuvent aider les astronomes à trouver des planètes cachées tournant autour d'autres étoiles : le mouvement oscillant d'une étoile permet aux scientifiques de calculer la masse qu'ils ne peuvent pas voir dans un système donné.","type":"unstyled","depth":0,"inlineStyleRanges":[],"entityRanges":[],"data":{}},{"key":"85k0v","text":"James O'Donoghue a réalisé une animation similaire de Pluton et de sa lune, Charon. Dans ce système, le barycentre est toujours à l'extérieur de Pluton.","type":"unstyled","depth":0,"inlineStyleRanges":[],"entityRanges":[],"data":{}},{"key":"dqh40","text":"","type":"atomic","depth":0,"inlineStyleRanges":[],"entityRanges":[],"data":{"type":"media","key":"dqh40","caption":null,"format":null,"iframely":{"meta":{"media":"player","site":"YouTube","author":"Dr James O'Donoghue","views":"144673","date":"2020-05-07T03:29:44.000Z","dislikes":"2","canonical":"https://www.youtube.com/watch?v=qF8-DP1PWmk","duration":25,"title":"Pluto and Charon are a fine example of how bodies orbit the center of mass (barycenter)","author_url":"https://www.youtube.com/channel/UCSaCQr2ppyNUY_kjnWY1yVQ","likes":"128","description":"Here the barycenter is completely outside of Pluto all the time, so you could say this is a (dwarf-)double planet system. Charon is 12% the mass of Pluto, and they're BOTH tidally locked!\nAbout tidal lock: here each body sees the same face of the other body all the time. That means the rotation periods AND orbit periods (around Barycenter) of BOTH bodies are the same; in this case 6.39 days. How convenient that we only have to remember 1 number for 4 parameters.\nIt's worth noting that tidal locking doesn't always mean two bodies face eachother, but it's usually the case. Mercury for example is in tidal lock with the Sun, but it rotates on its axis three times for every two orbits it makes around the Sun.\n\nImagery from: NASA / USGS / Solar System Scope processing https://www.solarsystemscope.com/textures/ under CC BY 4.0\nNASA ephemeris data: https://ssd.jpl.nasa.gov/horizons.cgi#top"},"links":{"player":[{"href":"https://www.youtube.com/embed/qF8-DP1PWmk?rel=0&showinfo=1","rel":["player","html5","accelerometer","clipboard-write","encrypted-media","gyroscope","picture-in-picture","ssl"],"type":"text/html","options":{"_start":{"label":"Start from","value":"","placeholder":"ex.: 11, 1m10s"},"_end":{"label":"End on","value":"","placeholder":"ex.: 11, 1m10s"}},"media":{"aspect-ratio":1.7777777777777777,"scrolling":"no"},"html":"

"},{"href":"https://www.youtube.com/embed/qF8-DP1PWmk?rel=0&showinfo=1&autoplay=1","rel":["player","html5","accelerometer","clipboard-write","encrypted-media","gyroscope","picture-in-picture","ssl","autoplay"],"type":"text/html","options":{"_start":{"label":"Start from","value":"","placeholder":"ex.: 11, 1m10s"},"_end":{"label":"End on","value":"","placeholder":"ex.: 11, 1m10s"}},"media":{"aspect-ratio":1.7777777777777777,"scrolling":"no"},"html":"

"}],"thumbnail":[{"href":"https://i.ytimg.com/vi/qF8-DP1PWmk/maxresdefault.jpg","rel":["thumbnail","ssl"],"type":"image/jpeg","media":{"width":1280,"height":720}},{"href":"https://i.ytimg.com/vi/qF8-DP1PWmk/mqdefault.jpg","rel":["thumbnail","ssl"],"type":"image/jpeg","media":{"width":320,"height":180}}],"icon":[{"href":"https://www.youtube.com/s/desktop/3e68fd4d/img/favicon_144.png","rel":["icon","ssl"],"type":"image/png","media":{"width":144,"height":144}},{"href":"https://www.youtube.com/s/desktop/3e68fd4d/img/favicon_96.png","rel":["icon","ssl"],"type":"image/png","media":{"width":96,"height":96}},{"href":"https://www.youtube.com/s/desktop/3e68fd4d/img/favicon_48.png","rel":["icon","ssl"],"type":"image/png","media":{"width":48,"height":48}},{"href":"https://www.youtube.com/s/desktop/3e68fd4d/img/favicon_32.png","rel":["icon","ssl"],"type":"image/png","media":{"width":32,"height":32}},{"href":"https://www.youtube.com/s/desktop/3e68fd4d/img/favicon.ico","rel":["shortcut","icon","ssl"],"type":"image/x-icon"}]},"rel":["player","html5","accelerometer","clipboard-write","encrypted-media","gyroscope","picture-in-picture","ssl"],"html":"

","options":{"_start":{"label":"Start from","value":"","placeholder":"ex.: 11, 1m10s"},"_end":{"label":"End on","value":"","placeholder":"ex.: 11, 1m10s"}}},"focusPoint":{"x":null,"y":null,"relativeX":null,"relativeY":null},"target":null,"rel":null}},{"key":"7namg","text":"Cela s'explique par le fait que la masse de Charon n'est pas beaucoup plus faible que celle de Pluton, et que la masse du système est donc répartie plus uniformément que celle de la Terre et de notre lune. Le barycentre se trouvant à l'extérieur de Pluton, James O'Donoghue explique que l'on pouvait en fait considérer qu'il s'agissait d'un \"système à deux planètes (naines)\" plutôt que d'une planète naine et de sa lune.","type":"unstyled","depth":0,"inlineStyleRanges":[],"entityRanges":[{"offset":274,"length":8,"key":3}],"data":{}},{"key":"3t55c","text":"Pendant son temps libre, James O'Donoghue a également réalisé des animations pour expliquer pourquoi les années bissextiles sont nécessaires, pourquoi vous n'avez probablement jamais vu un modèle du système solaire à l'échelle et à quel point la vitesse de la lumière est incroyablement lente.","type":"unstyled","depth":0,"inlineStyleRanges":[],"entityRanges":[{"offset":66,"length":10,"key":4}],"data":{}},{"key":"9rlv0","text":"Version originale : Morgan McFall-Johnsen/Insider","type":"unstyled","depth":0,"inlineStyleRanges":[],"entityRanges":[{"offset":20,"length":29,"key":5}],"data":{}},{"key":"ci5gt","text":"À lire aussi — Cette vidéo montre à quelle vitesse les planètes du système solaire tournent sur elles-mêmes","type":"unstyled","depth":0,"inlineStyleRanges":[{"offset":0,"length":107,"style":"ITALIC"},{"offset":0,"length":107,"style":"BOLD"}],"entityRanges":[{"offset":15,"length":92,"key":6}],"data":{}}],"entityMap":{"0":{"type":"LINK","mutability":"MUTABLE","data":{"url":"https://twitter.com/physicsJ","nofollow":true}},"1":{"type":"LINK","mutability":"MUTABLE","data":{"url":"https://twitter.com/physicsj/status/1279408365706211328?lang=en","nofollow":true}},"2":{"type":"LINK","mutability":"MUTABLE","data":{"children":"Cette simple animation montre de quoi est constituée la croûte terrestre","id":"c41bcec8-062a-480c-a090-5c895dd5f098","url":"https://www.businessinsider.fr/cette-simple-animation-montre-de-quoi-est-constituee-la-croute-terrestre-184517"}},"3":{"type":"LINK","mutability":"MUTABLE","data":{"url":"https://twitter.com/physicsJ/status/1258235218948841473","nofollow":true}},"4":{"type":"LINK","mutability":"MUTABLE","data":{"url":"https://www.youtube.com/channel/UCSaCQr2ppyNUY_kjnWY1yVQ","nofollow":true}},"5":{"type":"LINK","mutability":"MUTABLE","data":{"url":"https://www.businessinsider.fr/us/animation-shows-moon-orbits-barycenter-below-earth-surface-2021-3","nofollow":true}},"6":{"type":"LINK","mutability":"MUTABLE","data":{"children":"Cette vidéo montre à quelle vitesse les planètes du système solaire tournent sur elles-mêmes","id":"d5330158-db48-4085-bb0e-95bb99f7d0f5","url":"https://www.businessinsider.fr/cette-video-montre-a-quelle-vitesse-les-planetes-du-systeme-solaire-tournent-sur-elles-memes-174609"}}}}

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