{"id":881,"date":"2006-09-07T12:06:00","date_gmt":"2006-09-07T10:06:00","guid":{"rendered":"https:\/\/kids.esa.int\/supernovas\/"},"modified":"2026-10-08T00:33:19","modified_gmt":"2026-10-07T22:33:19","slug":"supernovas","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/fi\/supernovas\/","title":{"rendered":"Supernovat"},"content":{"rendered":"
\n

Ajoittain Linnunradamme valaistuu valtavan r\u00e4j\u00e4hdyksen seurauksena. T\u00e4m\u00e4 supernovana tunnettu v\u00e4kivaltainen ilmi\u00f6 merkitsee superj\u00e4ttil\u00e4isen \u2013 Auringosta moninkertaisesti suuremman raskaan t\u00e4hden \u2013 kuolemaa. Yksi Linnunradan viimeisimmist\u00e4 supernovista tapahtui noin 340 vuotta sitten Kassiopeian t\u00e4hdist\u00f6ss\u00e4, joten se tunnetaan nimell\u00e4 Kassiopeia A (Cas A).<\/p>\n<\/div>\n

Cas A sijaitsee 10 000 valovuoden p\u00e4\u00e4ss\u00e4 Maasta. T\u00e4htitieteelliset observatoriot, kuten NASA:n ja ESA:n yhteinen Hubble-avaruusteleskooppi, ovat tutkineet yksityiskohtaisesti t\u00e4t\u00e4 hehkuvan kaasun ja p\u00f6lyn j\u00e4\u00e4nn\u00f6spilve\u00e4.<\/p>\n

\"Zooming
Cassiopeia A:n l\u00e4hikuva<\/figcaption><\/figure>\n

Kuvissa n\u00e4kyy repaleinen materiaalirengas, joka liikkuu nopeasti poisp\u00e4in r\u00e4j\u00e4hdyspaikalta. Osa materiaalista liikkuu noin 50 miljoonan kilometrin tuntivauhdilla (tarpeeksi nopeasti matkustaakseen Maasta Kuuhun 30 sekunnissa!). Valtavat roskien py\u00f6rteet hehkuvat, koska supernovan ohikulkeva paineaalto on l\u00e4mmitt\u00e4nyt ne.<\/p>\n

Supernovar\u00e4j\u00e4hdyksi\u00e4 on useita erilaisia. Cas A r\u00e4j\u00e4hti, kun pieni t\u00e4hti, niin kutsuttu valkoinen k\u00e4\u00e4pi\u00f6, imi paljon ainetta l\u00e4heisest\u00e4 t\u00e4hdest\u00e4. Kaasun kertyess\u00e4 valkoinen k\u00e4\u00e4pi\u00f6 kuumeni ja aktivoitui niin paljon, ett\u00e4 se r\u00e4j\u00e4hti. Muut supernovat syntyv\u00e4t, kun massiivisten t\u00e4htien ytimiss\u00e4 loppuu ydinpolttoaine. Koska ydin ei en\u00e4\u00e4 pysty tuottamaan energiaa, se romahtaa ja tuhoaa t\u00e4hden.<\/p>\n

Supernovat ovat t\u00e4rkeit\u00e4, koska ne levitt\u00e4v\u00e4t t\u00e4htiainesta ymp\u00e4ri galaksia. L\u00e4hes kaikki Maassa (me mukaan lukien!) koostuu alkuaineista (kuten hiilest\u00e4 ja raudasta), jotka ovat per\u00e4isin t\u00e4st\u00e4 t\u00e4htip\u00f6lyst\u00e4.<\/p>","protected":false},"excerpt":{"rendered":"

Every now and again our Milky Way galaxy is lit up by a huge explosion. Known as a supernova, this violent event marks the death of a supergiant \u2013 a […]<\/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\/2006\/08\/hubble_s_view_of_supernova_explosion_cassiopeia_a2\/18245292-2-eng-GB\/Hubble_s_view_of_supernova_explosion_Cassiopeia_A.jpg","esa_banner_description":"Hubble\u2019s view of supernova explosion Cassiopeia A","esa_banner_credit":"NASA, ESA, and the Hubble Heritage (STScI\/AURA)-ESA\/Hubble Collaboration","esa_banner_licence":"ESA Standard Licence","esa_banner_detail_url":"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2006\/08\/Hubble_s_view_of_supernova_explosion_Cassiopeia_A2","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":[],"panel":[],"language":[],"age":[],"duration":[],"resource_type":[],"audience":[],"wf_post_folders":[],"class_list":["post-881","post","type-post","status-publish","format-standard","hentry","category-learn","category-our-universe","category-stars-and-galaxies"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/881","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=881"}],"version-history":[{"count":5,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/881\/revisions"}],"predecessor-version":[{"id":4717,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/881\/revisions\/4717"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/media?parent=881"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/categories?post=881"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/tags?post=881"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/panel?post=881"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/language?post=881"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/age?post=881"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/duration?post=881"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/resource_type?post=881"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/audience?post=881"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/wf_post_folders?post=881"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}