{"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\/fi\/what_is_gravity\/","title":{"rendered":"Mit\u00e4 on painovoima?"},"content":{"rendered":"
\n

Oletko koskaan miettinyt, miksi putoat aina maahan kolahdellen, riippumatta siit\u00e4, kuinka korkealle hypp\u00e4\u00e4t? Ihmiset esittiv\u00e4t saman kysymyksen jo 340 vuotta sitten. Silloin brittil\u00e4inen tiedemies nimelt\u00e4 Isaac Newton l\u00f6ysi painovoiman.<\/p>\n<\/div>\n

128125 Tarinassa kerrotaan, kuinka Isaac oli puutarhassaan, kun omena putosi h\u00e4nen p\u00e4\u00e4h\u00e4ns\u00e4. H\u00e4n hieroi mustelmaansa ja alkoi mietti\u00e4, miksi omena oli osunut h\u00e4neen eik\u00e4 lent\u00e4nyt sen sijaan yl\u00f6sp\u00e4in.<\/p>\n

Newton keksi, ett\u00e4 jonkin n\u00e4kym\u00e4tt\u00f6m\u00e4n voiman t\u00e4ytyi vet\u00e4\u00e4 omenaa kohti maata. H\u00e4n antoi t\u00e4lle voimalle nimen \u201cpainovoima\u201d \u2013 latinankielisest\u00e4 sanasta \u201cgravitas\u201d, joka tarkoittaa \u201cpaino\u201d.<\/p>\n

\"Newton's
Newtonin tykki<\/figcaption><\/figure>\n

Newton tajusi, ett\u00e4 jokainen esine maailmankaikkeudessa vet\u00e4\u00e4 puoleensa jokaista muuta esinett\u00e4 maailmankaikkeudessa. Jopa omena vet\u00e4\u00e4 hieman puoleensa kaikkea ymp\u00e4rill\u00e4\u00e4n olevaa.<\/p>\n

Juuri painovoima pit\u00e4\u00e4 Kuun kiertoradalla Maan ymp\u00e4rill\u00e4, ja painovoima mahdollistaa sen, ett\u00e4 Aurinko pit\u00e4\u00e4 planeettaperheens\u00e4 koossa. Auringon ja Kuun vetovoima aiheuttaa my\u00f6s Maan merien vuoroveden.<\/p>\n

Painovoiman voimakkuus riippuu kuitenkin esineen koosta ja tiheydest\u00e4 \u2013 siit\u00e4, mit\u00e4 tiedemiehet kutsuvat sen \u201cmassaksi\u201d. Pienen omenan painovoima on liian heikko voittamaan valtavan Maan vetovoimaa, joten se putoaa kohti planeetan keskustaa.<\/p>\n

Kohteen painovoiman vaikutus heikkenee et\u00e4isyyden kasvaessa. Everestin huipulla oleva kiipeilij\u00e4 painaa hieman v\u00e4hemm\u00e4n kuin merenpinnan tasolla. Jos avaruusalus matkustaa riitt\u00e4v\u00e4n kauas Maasta, se p\u00e4\u00e4see lopulta kokonaan planeetan painovoiman vaikutuksen ulkopuolelle.<\/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\/fi\/wp-json\/wp\/v2\/posts\/35","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/comments?post=35"}],"version-history":[{"count":4,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/35\/revisions"}],"predecessor-version":[{"id":4271,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/35\/revisions\/4271"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/media?parent=35"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/categories?post=35"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/tags?post=35"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/panel?post=35"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/language?post=35"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/age?post=35"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/duration?post=35"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/resource_type?post=35"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/audience?post=35"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/wf_post_folders?post=35"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}