{"id":196,"date":"2021-12-02T12:44:26","date_gmt":"2021-12-02T11:44:26","guid":{"rendered":"https:\/\/kids.esa.int\/stars2\/"},"modified":"2026-10-08T00:25:22","modified_gmt":"2026-10-07T22:25:22","slug":"stars2","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/fi\/stars2\/","title":{"rendered":"T\u00e4hdet"},"content":{"rendered":"
\n

Aivan kuten ihmiset, my\u00f6s 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 n\u00e4ht\u00e4viss\u00e4 paljaalla silm\u00e4ll\u00e4.<\/p>\n<\/div>\n

Miljardeja vuosia syntym\u00e4ns\u00e4 j\u00e4lkeen, kun Auringon kaltainen keskikokoinen t\u00e4hti l\u00e4hestyy elinkaarensa loppua, se laajenee punaiseksi j\u00e4ttil\u00e4iseksi. Sen halkaisija voi olla miljoonia kilometrej\u00e4 \u2013 kun t\u00e4m\u00e4 tapahtuu Auringolle, se on niin suuri, ett\u00e4 se nielaisi Merkuriuksen ja Venuksen!<\/p>\n

Kun t\u00e4hti on puhaltanut ulommat kaasukerroksensa pois, se romahtaa ja muodostaa eritt\u00e4in tihe\u00e4n valkoisen k\u00e4\u00e4pi\u00f6n. Yksi teelusikallinen valkoisen k\u00e4\u00e4pi\u00f6n ainetta painaisi jopa 100 tonnia! Miljardien vuosien kuluessa valkoinen k\u00e4\u00e4pi\u00f6 j\u00e4\u00e4htyy ja muuttuu n\u00e4kym\u00e4tt\u00f6m\u00e4ksi. Mutta \u00e4l\u00e4 huoli, sit\u00e4 ei tapahdu Aurinkollemme viel\u00e4 noin 5 miljardiin vuoteen!<\/p>\n

Pienet t\u00e4hdet el\u00e4v\u00e4t pitk\u00e4\u00e4n, yli 10 miljardia vuotta. Niiden kuolemaa ei ole koskaan havaittu, mutta niiden uskotaan p\u00e4\u00e4ttyv\u00e4n el\u00e4m\u00e4ns\u00e4 hiljaisesti ja lopulta sammuvan v\u00e4hitellen.<\/p>\n

\"Supernova
Supernovan j\u00e4\u00e4nn\u00f6s<\/figcaption><\/figure>\n

Suurimmat t\u00e4hdet p\u00e4\u00e4ttyv\u00e4t hyvin \u00e4killisesti. El\u00e4m\u00e4ns\u00e4 loppuvaiheessa ne turpoavat punaisiksi superj\u00e4ttil\u00e4isiksi, ennen kuin ne lopulta r\u00e4j\u00e4ht\u00e4v\u00e4t valtavassa supernovar\u00e4j\u00e4hdyksess\u00e4.<\/p>\n

Noin viikon ajan supernova loistaa kirkkaammin kuin mik\u00e4\u00e4n muu t\u00e4hti galaksissaan. Sitten sen kirkkaus hiipuu nopeasti. J\u00e4ljelle j\u00e4\u00e4 vain pieni, tihe\u00e4 kappale \u2013 neutronit\u00e4hti tai musta aukko \u2013 jota ymp\u00e4r\u00f6i laajeneva, eritt\u00e4in kuuman kaasun pilvi.<\/p>\n

Superj\u00e4ttil\u00e4ist\u00e4hdess\u00e4 syntyneet alkuaineet (kuten happi, hiili ja rauta) levi\u00e4v\u00e4t avaruuteen. T\u00e4st\u00e4 t\u00e4htip\u00f6lyst\u00e4 syntyy lopulta uusia t\u00e4hti\u00e4 ja planeettoja!<\/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-196","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\/196","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=196"}],"version-history":[{"count":4,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/196\/revisions"}],"predecessor-version":[{"id":4352,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/196\/revisions\/4352"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/media?parent=196"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/categories?post=196"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/tags?post=196"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/panel?post=196"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/language?post=196"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/age?post=196"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/duration?post=196"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/resource_type?post=196"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/audience?post=196"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/wf_post_folders?post=196"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}