{"id":35,"date":"2005-06-30T09:17:00","date_gmt":"2005-06-30T07:17:00","guid":{"rendered":"https:\/\/kids.esa.int\/what_is_gravity\/"},"modified":"2026-10-08T00:23:19","modified_gmt":"2026-10-07T22:23:19","slug":"what_is_gravity","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/cs\/what_is_gravity\/","title":{"rendered":"Co je to gravitace?"},"content":{"rendered":"
\n

P\u0159em\u00fd\u0161leli jste n\u011bkdy nad t\u00edm, pro\u010d v\u017edycky dopadnete na zem s n\u00e1razem, a\u0165 u\u017e vysko\u010d\u00edte jakkoli vysoko? Stejnou ot\u00e1zku si kladli lid\u00e9 u\u017e p\u0159ed 340 lety. Tehdy objevil britsk\u00fd v\u011bdec Isaac Newton gravita\u010dn\u00ed s\u00edlu.<\/p>\n<\/div>\n

128125 P\u0159\u00edb\u011bh vypr\u00e1v\u00ed, jak byl Isaac ve sv\u00e9 zahrad\u011b, kdy\u017e mu na hlavu spadlo jablko. Zat\u00edmco si mas\u00edroval mod\u0159inu, za\u010dal p\u0159em\u00fd\u0161let, pro\u010d ho to jablko zas\u00e1hlo, m\u00edsto aby vylet\u011blo nahoru.<\/p>\n

Newton p\u0159i\u0161el s my\u0161lenkou, \u017ee jablko k Zemi mus\u00ed p\u0159itahovat n\u011bjak\u00e1 neviditeln\u00e1 s\u00edla. Tuto s\u00edlu pojmenoval \u201cgravitace\u201d \u2013 podle latinsk\u00e9ho slova \u201cgravitas\u201d, co\u017e znamen\u00e1 \u201cv\u00e1ha\u201d.<\/p>\n

\"Newton's
Newtonovo d\u011blo<\/figcaption><\/figure>\n

Newton si uv\u011bdomil, \u017ee ka\u017ed\u00fd objekt ve vesm\u00edru p\u0159itahuje ka\u017ed\u00fd jin\u00fd objekt ve vesm\u00edru. Dokonce i jablko lehce p\u0159itahuje v\u0161e, co se nach\u00e1z\u00ed v jeho okol\u00ed.<\/p>\n

Pr\u00e1v\u011b gravitace udr\u017euje M\u011bs\u00edc na ob\u011b\u017en\u00e9 dr\u00e1ze kolem Zem\u011b a pr\u00e1v\u011b gravitace umo\u017e\u0148uje Slunci udr\u017eet si svou skupinu planet. Gravita\u010dn\u00ed s\u00edla Slunce a M\u011bs\u00edce tak\u00e9 zp\u016fsobuje p\u0159\u00edlivy a odlivy v oce\u00e1nech.<\/p>\n

S\u00edla gravitace v\u0161ak z\u00e1vis\u00ed na velikosti a hustot\u011b t\u011blesa \u2013 na tom, co v\u011bdci naz\u00fdvaj\u00ed jeho \u201chmotnost\u00ed\u201d. Gravita\u010dn\u00ed s\u00edla toho mal\u00e9ho jablka je p\u0159\u00edli\u0161 slab\u00e1 na to, aby p\u0159ekonala p\u0159ita\u017elivou s\u00edlu obrovsk\u00e9 Zem\u011b, a proto jablko pad\u00e1 sm\u011brem ke st\u0159edu planety.<\/p>\n

Gravita\u010dn\u00ed p\u0159ita\u017elivost objektu kles\u00e1 s rostouc\u00ed vzd\u00e1lenost\u00ed od n\u011bj. Horolezec na vrcholu Mount Everestu v\u00e1\u017e\u00ed o n\u011bco m\u00e9n\u011b ne\u017e na \u00farovni mo\u0159sk\u00e9 hladiny. Pokud se kosmick\u00e1 lo\u010f vzd\u00e1l\u00ed od Zem\u011b dostate\u010dn\u011b daleko, nakonec se zcela vyman\u00ed z gravita\u010dn\u00edho pole planety.<\/p>","protected":false},"excerpt":{"rendered":"

Have you ever wondered why you always fall back to the ground with a bump, no matter how high you jump? People were asking the same question 340 years ago. […]<\/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\/2002\/01\/sir_isaac_newton_1642-17272\/17864713-3-eng-GB\/Sir_Isaac_Newton_1642-1727.jpg","esa_banner_description":"Sir Isaac Newton, 1642-1727","esa_banner_credit":"Isaac Newton Institute for Mathematical Studies","esa_banner_licence":"ESA Standard Licence","esa_banner_detail_url":"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2002\/01\/Sir_Isaac_Newton_1642-17272","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":[2],"panel":[],"language":[],"age":[],"duration":[],"resource_type":[],"audience":[],"wf_post_folders":[],"class_list":["post-35","post","type-post","status-publish","format-standard","hentry","category-learn","category-our-universe","category-story-of-the-universe","tag-background-article"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/posts\/35","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=35"}],"version-history":[{"count":4,"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/posts\/35\/revisions"}],"predecessor-version":[{"id":4271,"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/posts\/35\/revisions\/4271"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/media?parent=35"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/categories?post=35"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/tags?post=35"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/panel?post=35"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/language?post=35"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/age?post=35"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/duration?post=35"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/resource_type?post=35"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/audience?post=35"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/cs\/wp-json\/wp\/v2\/wf_post_folders?post=35"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}