{"id":589,"date":"2004-11-15T13:56:00","date_gmt":"2004-11-15T12:56:00","guid":{"rendered":"https:\/\/kids.esa.int\/the_big_bang\/"},"modified":"2026-10-08T00:29:59","modified_gmt":"2026-10-07T22:29:59","slug":"the_big_bang","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/fi\/the_big_bang\/","title":{"rendered":"Alkur\u00e4j\u00e4hdys"},"content":{"rendered":"<div class=\"lede\">\n<p>Suurin osa t\u00e4htitieteilij\u00f6ist\u00e4 uskoo, ett\u00e4 maailmankaikkeus sai alkunsa suuresta r\u00e4j\u00e4hdyksest\u00e4 noin 14 miljardia vuotta sitten. Tuolloin koko maailmankaikkeus oli kuplan sis\u00e4ll\u00e4, joka oli tuhansia kertoja pienempi kuin neulanp\u00e4\u00e4. Se oli kuumempi ja tihe\u00e4mpi kuin mik\u00e4\u00e4n, mit\u00e4 voimme kuvitella.<\/p>\n<\/div>\n<p>Sitten se r\u00e4j\u00e4hti yht\u00e4kki\u00e4. Meille tuttu maailmankaikkeus syntyi. Aika, avaruus ja aine saivat alkunsa alkur\u00e4j\u00e4hdyksess\u00e4. Sekunnin murto-osassa maailmankaikkeus kasvoi pienemm\u00e4st\u00e4 kuin yksi atomi suuremmaksi kuin galaksi. Ja se jatkoi kasvuaan uskomattomalla vauhdilla. Se laajenee edelleen t\u00e4n\u00e4kin p\u00e4iv\u00e4n\u00e4.<\/p>\n<p>Kun maailmankaikkeus laajeni ja j\u00e4\u00e4htyi, energia muuttui aineen ja antiaineen hiukkasiksi. N\u00e4m\u00e4 kaksi vastakkaista hiukkastyyppi\u00e4 tuhosivat toisensa suurelta osin. Osa aineesta kuitenkin s\u00e4ilyi. Vakaampia hiukkasia, joita kutsutaan protoneiksi ja neutroneiksi, alkoi muodostua, kun maailmankaikkeus oli ollut olemassa yhden sekunnin.<\/p>\n<p>Seuraavien kolmen minuutin aikana l\u00e4mp\u00f6tila laski alle miljardi celsiusastetta. Ilma oli nyt riitt\u00e4v\u00e4n viile\u00e4\u00e4, jotta protonit ja neutronit pystyiv\u00e4t yhdistym\u00e4\u00e4n ja muodostamaan vety- ja heliumytimi\u00e4.<\/p>\n<p>300 000 vuoden kuluttua maailmankaikkeus oli j\u00e4\u00e4htynyt noin 3 000 asteeseen. Atomien ytimet pystyiv\u00e4t vihdoin sitomaan elektroneja ja muodostamaan atomeja. Maailmankaikkeus t\u00e4yttyi vety- ja heliumkaasupilvist\u00e4.<\/p>","protected":false},"excerpt":{"rendered":"<p>Most astronomers believe the Universe began in a Big Bang about 14 billion years ago. At that time, the entire Universe was inside a bubble that was thousands of times [&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\/2014\/06\/nearby_galaxy\/17883658-2-eng-GB\/Nearby_galaxy.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\/2014\/06\/Nearby_galaxy","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-589","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\/589","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=589"}],"version-history":[{"count":1,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/589\/revisions"}],"predecessor-version":[{"id":1732,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/589\/revisions\/1732"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/media?parent=589"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/categories?post=589"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/tags?post=589"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/panel?post=589"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/language?post=589"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/age?post=589"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/duration?post=589"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/resource_type?post=589"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/audience?post=589"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/wf_post_folders?post=589"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}