{"id":879,"date":"2006-07-27T09:13:00","date_gmt":"2006-07-27T07:13:00","guid":{"rendered":"https:\/\/kids.esa.int\/methane_lakes_and_ice_pebbles\/"},"modified":"2026-10-08T00:33:18","modified_gmt":"2026-10-07T22:33:18","slug":"methane_lakes_and_ice_pebbles","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/fi\/methane_lakes_and_ice_pebbles\/","title":{"rendered":"Metaanij\u00e4rvet ja j\u00e4\u00e4kivet"},"content":{"rendered":"
\n

Saturnuksen kuu Titan on yksi aurinkokunnan suurimmista ja kiehtovimmista kuista. Valitettavasti sen pinta on piilossa paksun oranssinv\u00e4risen pilvipeitteen alla. Viel\u00e4 \u00e4skett\u00e4in kukaan ei tiennyt, millainen Titanin pinta on.<\/p>\n<\/div>\n

Yksi tapa l\u00e4p\u00e4ist\u00e4 pilvikerros on k\u00e4ytt\u00e4\u00e4 NASA:n Cassini-avaruusluotaimen tutkaa. Cassinista l\u00e4hetetyt radiosignaalit kulkevat pilven l\u00e4pi ja heijastuvat takaisin pinnalta. Tutkijoilla on viime aikoina onnistunut havaita monia tummia alueita tutkimalla n\u00e4it\u00e4 kaikuja. Osa n\u00e4ist\u00e4 alueista liittyy kapeisiin, mutkaisiin kanaviin \u2013 mahdollisesti jokiin.<\/p>\n

Vaikuttaa todenn\u00e4k\u00f6iselt\u00e4, ett\u00e4 tutkakuvien sile\u00e4t, tummat alueet ovat j\u00e4rvi\u00e4. Titanin pintal\u00e4mp\u00f6tila on kuitenkin -180 \u00b0C, joten ne eiv\u00e4t voi sis\u00e4lt\u00e4\u00e4 vett\u00e4. Sen sijaan ne n\u00e4ytt\u00e4v\u00e4t koostuvan nestem\u00e4isest\u00e4 metaanista tai etaanista. (Maapallolla metaanikaasua poltetaan kattiloissa ja liesiss\u00e4.)<\/p>\n

\"First
Ensimm\u00e4inen v\u00e4rikuva Titanin pinnasta<\/figcaption><\/figure>\n

Monet toivoivat, ett\u00e4 ESA:n Huygens-luotain laskeutuisi metaanij\u00e4rveen laskeutuessaan pinnalle 14. tammikuuta 2005. Sen kamera kuitenkin n\u00e4ytti kuivan, j\u00e4\u00e4kivill\u00e4 peitetyn tasangon.<\/p>\n

T\u00e4m\u00e4n huikean menestyksen j\u00e4lkeen tutkijat ovat l\u00f6yt\u00e4neet ep\u00e4tavallisen tavan saada lis\u00e4tietoa Huygensin ymp\u00e4rist\u00f6st\u00e4. Avaintekij\u00e4n\u00e4 oli ep\u00e4tavallinen nousu- ja laskuvaihtelu Huygensin Cassinille l\u00e4hett\u00e4m\u00e4ss\u00e4 radiosignaalissa. Osa radios\u00e4teest\u00e4 heijastui pinnasta eik\u00e4 kulkenut suoraan Cassiniin. Signaalin analysointi osoitti, ett\u00e4 pinta on melko tasainen jopa 2 km:n et\u00e4isyydell\u00e4 luotaimesta. T\u00e4m\u00e4 kuiva j\u00e4rvenpohja on p\u00e4\u00e4osin peitetty halkaisijaltaan noin 5\u201310 cm:n kokoisilla j\u00e4\u00e4kivill\u00e4.<\/p>","protected":false},"excerpt":{"rendered":"

Saturn\u2019s moon Titan is one of the largest and most fascinating satellites in the Solar System. Unfortunately, its surface is hidden beneath a thick blanket of orange cloud. Until recently, […]<\/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\/07\/lakes_on_titan2\/18249176-2-eng-GB\/Lakes_on_Titan.jpg","esa_banner_description":"Lakes on Titan","esa_banner_credit":"NASA\/JPL","esa_banner_licence":"ESA Standard Licence","esa_banner_detail_url":"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2006\/07\/Lakes_on_Titan2","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":[10,11,12],"tags":[],"panel":[],"language":[],"age":[],"duration":[],"resource_type":[],"audience":[],"wf_post_folders":[],"class_list":["post-879","post","type-post","status-publish","format-standard","hentry","category-learn","category-our-universe","category-planets-and-moons"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/879","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=879"}],"version-history":[{"count":5,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/879\/revisions"}],"predecessor-version":[{"id":4716,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/879\/revisions\/4716"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/media?parent=879"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/categories?post=879"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/tags?post=879"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/panel?post=879"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/language?post=879"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/age?post=879"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/duration?post=879"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/resource_type?post=879"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/audience?post=879"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/wf_post_folders?post=879"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}