{"id":484,"date":"2016-06-06T07:56:00","date_gmt":"2016-06-06T05:56:00","guid":{"rendered":"https:\/\/kids.esa.int\/gravity\/"},"modified":"2026-10-08T00:28:44","modified_gmt":"2026-10-07T22:28:44","slug":"gravity","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/cs\/gravity\/","title":{"rendered":"Gravitace!"},"content":{"rendered":"<div class=\"lede\">\n<p>Vid\u011bli jste n\u011bkdy, jak z stromu spadlo ovoce nebo n\u011bjak\u00fd p\u0159edm\u011bt? A zkusili jste n\u011bkdy hodit k\u00e1men a sledovat, jak pad\u00e1? Tato s\u00edla, kter\u00e1 v\u011bci \u2018stahuje dol\u016f\u2019, se naz\u00fdv\u00e1 gravita\u010dn\u00ed s\u00edla.<\/p>\n<\/div>\n<p>Zem\u011b na n\u00e1s neust\u00e1le p\u016fsob\u00ed svou gravita\u010dn\u00ed silou. To je d\u016fvod, pro\u010d m\u00e1me nohy v\u017edy na zemi. Nemus\u00edme v\u0161ak b\u00fdt v p\u0159\u00edm\u00e9m kontaktu se Zem\u00ed, aby na n\u00e1s p\u016fsobila jej\u00ed p\u0159ita\u017elivost; sta\u010d\u00ed, kdy\u017e nejsme p\u0159\u00edli\u0161 daleko, a stejn\u00e9 s\u00edly na n\u00e1s p\u016fsob\u00ed. Proto na\u0161e planeta ob\u00edh\u00e1 kolem Slunce a M\u011bs\u00edc ob\u00edh\u00e1 kolem Zem\u011b.<\/p>\n<p>Gravita\u010dn\u00ed s\u00edla je d\u00e1na hmotnost\u00ed t\u011blesa. Gravita\u010dn\u00ed s\u00edla mezi dv\u011bma t\u011blesy je \u00fam\u011brn\u00e1 jejich hmotnostem a velmi rychle kles\u00e1, jakmile je od sebe odd\u00e1l\u00edme. Ve skute\u010dnosti p\u0159itahujeme i my ostatn\u00ed t\u011blesa \u2018na\u0161\u00ed\u2019 gravita\u010dn\u00ed silou, ale jsme p\u0159\u00edli\u0161 lehc\u00ed na to, abychom jej\u00ed \u00fa\u010dinky mohli pozorovat! Slunce je v\u0161ak tak velk\u00e9, \u017ee n\u00e1s dok\u00e1\u017ee udr\u017eet bl\u00edzko u sebe, i kdy\u017e je tak daleko. Svou gravita\u010dn\u00ed s\u00edlu vyv\u00edj\u00ed i M\u011bs\u00edc; jeliko\u017e je men\u0161\u00ed a leh\u010d\u00ed ne\u017e Zem\u011b, kdybychom se na n\u011bm mohli zv\u00e1\u017eit, zjistili bychom, \u017ee v\u00e1\u017e\u00edme asi \u0161estinu toho, co na Zemi.<\/p>\n<p>\u010clov\u011bk by se mohl zeptat, pro\u010d M\u011bs\u00edc nespadne na Zemi jako jablko ze stromu. D\u016fvodem je, \u017ee M\u011bs\u00edc nikdy nestoj\u00ed na m\u00edst\u011b. Neust\u00e1le se kolem n\u00e1s pohybuje. Bez gravita\u010dn\u00ed s\u00edly Zem\u011b by prost\u011b odplul do vesm\u00edru. Pr\u00e1v\u011b tato kombinace rychlosti a vzd\u00e1lenosti od Zem\u011b umo\u017e\u0148uje M\u011bs\u00edci udr\u017eovat rovnov\u00e1hu mezi p\u00e1dem a \u00fanikem. Kdyby byl rychlej\u0161\u00ed, unikl by; kdyby byl pomalej\u0161\u00ed, spadl by!<\/p>\n<p>\u0158ekli jsme, \u017ee s\u00edla gravitace z\u00e1vis\u00ed tak\u00e9 na vzd\u00e1lenosti. Kdybychom se dostali dostate\u010dn\u011b daleko, mohli bychom se vymanit z jej\u00edho vlivu. Pr\u00e1v\u011b o to se sna\u017e\u00edme s kosmick\u00fdmi lod\u011bmi. Mus\u00edme dos\u00e1hnout a p\u0159ekro\u010dit takzvanou \u2018\u00fanikovou rychlost\u2019, kter\u00e1 \u010din\u00ed p\u0159ibli\u017en\u011b 11,2 km\/s (p\u0159i takov\u00e9 rychlosti bychom se z Lond\u00fdna do New Yorku dostali za pouh\u00fdch deset minut!). Jakmile raketopl\u00e1n t\u00e9to rychlosti dos\u00e1hne, m\u016f\u017ee voln\u011b cestovat po Slune\u010dn\u00ed soustav\u011b.<\/p>\n<p>Uvnit\u0159 raketopl\u00e1nu na ob\u011b\u017en\u00e9 dr\u00e1ze nepoci\u0165ujeme gravita\u010dn\u00ed s\u00edlu Zem\u011b. P\u0159edm\u011bty nepadaj\u00ed, ale vzn\u00e1\u0161ej\u00ed se; kdy\u017e vysko\u010d\u00edte, nepadnete zp\u00e1tky dol\u016f. Tot\u00e9\u017e se d\u011bje astronaut\u016fm, kdy\u017e se nach\u00e1zej\u00ed na vesm\u00edrn\u00fdch stanic\u00edch ob\u00edhaj\u00edc\u00edch kolem Zem\u011b!<\/p>\n<nav class=\"related\" aria-label=\"Souvisej\u00edc\u00ed\">\n<h2 class=\"related__heading\">Souvisej\u00edc\u00ed<\/h2>\n<div class=\"grid related__grid\">\n<div class=\"grid-item\">\n<article class=\"card focuson agency\"><a class=\"card__link\" href=\"\/cs\/maanen_jorden_og_tyngdekraften2\/\"><\/p>\n<figure class=\"thumbnail\"><span class=\"dimmer\"><\/span><\/figure>\n<header class=\"entry\">\n<h3 class=\"heading\">d\u00e1n\u0161tina<\/h3>\n<\/header>\n<p><\/a><\/article>\n<\/div>\n<div class=\"grid-item\">\n<article class=\"card focuson agency\"><a class=\"card__link\" href=\"\/cs\/de_maan_de_aarde_en_zwaartekracht\/\"><\/p>\n<figure class=\"thumbnail\"><span class=\"dimmer\"><\/span><\/figure>\n<header class=\"entry\">\n<h3 class=\"heading\">nizozem\u0161tina<\/h3>\n<\/header>\n<p><\/a><\/article>\n<\/div>\n<div class=\"grid-item\">\n<article class=\"card focuson agency\"><a class=\"card__link\" href=\"\/cs\/la_lune_la_terre_et_la_gravite\/\"><\/p>\n<figure class=\"thumbnail\"><span class=\"dimmer\"><\/span><\/figure>\n<header class=\"entry\">\n<h3 class=\"heading\">Francouz\u0161tina<\/h3>\n<\/header>\n<p><\/a><\/article>\n<\/div>\n<div class=\"grid-item\">\n<article class=\"card focuson agency\"><a class=\"card__link\" href=\"\/cs\/mond_erde_und_schwerkraft\/\"><\/p>\n<figure class=\"thumbnail\"><span class=\"dimmer\"><\/span><\/figure>\n<header class=\"entry\">\n<h3 class=\"heading\">n\u011bm\u010dina<\/h3>\n<\/header>\n<p><\/a><\/article>\n<\/div>\n<div class=\"grid-item\">\n<article class=\"card focuson agency\"><a class=\"card__link\" href=\"\/cs\/la_luna_la_terra_e_la_gravita\/\"><\/p>\n<figure class=\"thumbnail\"><span class=\"dimmer\"><\/span><\/figure>\n<header class=\"entry\">\n<h3 class=\"heading\">italsk\u00fd<\/h3>\n<\/header>\n<p><\/a><\/article>\n<\/div>\n<div class=\"grid-item\">\n<article class=\"card focuson agency\"><a class=\"card__link\" href=\"\/cs\/maanen_jorden_og_tyngdekraften\/\"><\/p>\n<figure class=\"thumbnail\"><span class=\"dimmer\"><\/span><\/figure>\n<header class=\"entry\">\n<h3 class=\"heading\">nor\u0161tina<\/h3>\n<\/header>\n<p><\/a><\/article>\n<\/div>\n<div class=\"grid-item\">\n<article class=\"card focuson agency\"><a class=\"card__link\" href=\"\/cs\/ksiezyc_ziemia_i_grawitacja\/\"><\/p>\n<figure class=\"thumbnail\"><span class=\"dimmer\"><\/span><\/figure>\n<header class=\"entry\">\n<h3 class=\"heading\">pol\u0161tina<\/h3>\n<\/header>\n<p><\/a><\/article>\n<\/div>\n<div class=\"grid-item\">\n<article class=\"card focuson agency\"><a class=\"card__link\" href=\"\/cs\/la_luna_la_tierra_y_la_gravedad\/\"><\/p>\n<figure class=\"thumbnail\"><span class=\"dimmer\"><\/span><\/figure>\n<header class=\"entry\">\n<h3 class=\"heading\">\u0161pan\u011bl\u0161tina<\/h3>\n<\/header>\n<p><\/a><\/article>\n<\/div>\n<div class=\"grid-item\">\n<article class=\"card focuson agency\"><a class=\"card__link\" href=\"\/cs\/maanen_jorden_och_gravitation\/\"><\/p>\n<figure class=\"thumbnail\"><span class=\"dimmer\"><\/span><\/figure>\n<header class=\"entry\">\n<h3 class=\"heading\">\u0160v\u00e9d\u0161tina<\/h3>\n<\/header>\n<p><\/a><\/article>\n<\/div>\n<\/div>\n<\/nav>","protected":false},"excerpt":{"rendered":"<p>Have you ever seen a fruit or object falling from a tree? And have you ever tried to throw a stone and watch it fall? This force that \u2018brings down\u2019 [&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\/2016\/06\/gravity_apple_newton\/17897755-2-eng-GB\/Gravity_apple_Newton.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\/2016\/06\/Gravity_apple_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":[10,11,19],"tags":[],"panel":[],"language":[],"age":[],"duration":[],"resource_type":[],"audience":[],"wf_post_folders":[],"class_list":["post-484","post","type-post","status-publish","format-standard","hentry","category-learn","category-our-universe","category-story-of-the-universe"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/posts\/484","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/comments?post=484"}],"version-history":[{"count":1,"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/posts\/484\/revisions"}],"predecessor-version":[{"id":1627,"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/posts\/484\/revisions\/1627"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/media?parent=484"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/categories?post=484"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/tags?post=484"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/panel?post=484"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/language?post=484"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/age?post=484"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/duration?post=484"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/resource_type?post=484"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/audience?post=484"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/wf_post_folders?post=484"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}