{"id":925,"date":"2004-11-15T14:00:00","date_gmt":"2004-11-15T13:00:00","guid":{"rendered":"https:\/\/kids.esa.int\/star_birth\/"},"modified":"2026-10-08T00:33:50","modified_gmt":"2026-10-07T22:33:50","slug":"star_birth","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/fi\/star_birth\/","title":{"rendered":"T\u00e4hden synty"},"content":{"rendered":"
\n

Ihmisten tavoin t\u00e4hdet syntyv\u00e4t, vanhenevat ja kuolevat. Niiden syntypaikat ovat valtavia, kylmi\u00e4 kaasu- ja p\u00f6lypilvi\u00e4, joita kutsutaan \u2018sumuksiksi\u2019. Tunnetuin n\u00e4ist\u00e4 on Orionin sumu, joka on juuri ja juuri n\u00e4kyviss\u00e4 paljaalla silm\u00e4ll\u00e4.<\/p>\n<\/div>\n

N\u00e4m\u00e4 pilvet alkavat kutistua oman painovoimansa vaikutuksesta. Pilven pienentyess\u00e4 se hajoaa palasiksi. Jokainen pala kuumenee ja tiivistyy lopulta niin paljon, ett\u00e4 siin\u00e4 alkaa tapahtua ydinreaktioita. Kun l\u00e4mp\u00f6tila nousee 10 miljoonaan celsiusasteeseen, palasta tulee uusi t\u00e4hti.<\/p>\n

Syntym\u00e4ns\u00e4 j\u00e4lkeen useimmat nuoret t\u00e4hdet sijaitsevat kaasun ja p\u00f6lyn muodostaman litte\u00e4n kiekon keskell\u00e4. Suurin osa t\u00e4st\u00e4 aineesta puhalletaan lopulta pois t\u00e4hden s\u00e4teilyn vaikutuksesta. Ennen kuin n\u00e4in tapahtuu, keskust\u00e4hden ymp\u00e4rille voi muodostua planeettoja.<\/p>\n

\"Star-forming
ISO:n kuvaama t\u00e4htien muodostumista edist\u00e4v\u00e4 pime\u00e4 pilvi<\/figcaption><\/figure>\n

Infrapunaobservatoriot pystyv\u00e4t havaitsemaan l\u00e4mp\u00f6\u00e4, jota s\u00e4teilev\u00e4t n\u00e4kym\u00e4tt\u00f6m\u00e4t t\u00e4hdet, jotka ovat muodostumassa t\u00e4llaisten pilvien sis\u00e4ll\u00e4. Yksi tehokkaimmista n\u00e4ist\u00e4 on ESA:n Herschel-avaruusobservatorio, joka laukaistiin toukokuussa 2009. Herschel tutkii v\u00e4hint\u00e4\u00e4n kolmen vuoden ajan p\u00f6lyisi\u00e4 pilvi\u00e4, joissa t\u00e4hdet \u2013 niin suuret kuin pienetkin \u2013 syntyv\u00e4t.<\/p>","protected":false},"excerpt":{"rendered":"

Like people, stars are born, they grow old and they die. Their birth places are huge, cold clouds of gas and dust, known as ‘nebulas’. The most famous of these […]<\/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\/2004\/01\/nearby_galaxy_ngc_1569_is_a_hotbed_of_star_birth_activity2\/17880180-2-eng-GB\/Nearby_galaxy_NGC_1569_is_a_hotbed_of_star_birth_activity.jpg","esa_banner_description":"Nearby galaxy NGC 1569 is a 'hotbed' of star birth activity","esa_banner_credit":"ESA, NASA and Peter Anders (G\u00f6ttingen University Galaxy Evolution Group, Germany)","esa_banner_licence":"ESA Standard Licence","esa_banner_detail_url":"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2004\/01\/Nearby_galaxy_NGC_1569_is_a_hotbed_of_star_birth_activity2","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":[10,11,21],"tags":[2],"panel":[],"language":[],"age":[],"duration":[],"resource_type":[],"audience":[],"wf_post_folders":[],"class_list":["post-925","post","type-post","status-publish","format-standard","hentry","category-learn","category-our-universe","category-stars-and-galaxies","tag-background-article"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/925","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=925"}],"version-history":[{"count":4,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/925\/revisions"}],"predecessor-version":[{"id":4742,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/925\/revisions\/4742"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/media?parent=925"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/categories?post=925"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/tags?post=925"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/panel?post=925"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/language?post=925"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/age?post=925"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/duration?post=925"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/resource_type?post=925"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/audience?post=925"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/wf_post_folders?post=925"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}