{"id":1133,"date":"2004-11-16T08:14:00","date_gmt":"2004-11-16T07:14:00","guid":{"rendered":"https:\/\/kids.esa.int\/planets_and_moons_life_on_earth\/"},"modified":"2026-10-08T00:36:23","modified_gmt":"2026-10-07T22:36:23","slug":"planets_and_moons_life_on_earth","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/fi\/planets_and_moons_life_on_earth\/","title":{"rendered":"El\u00e4m\u00e4 maapallolla"},"content":{"rendered":"
\n

Muinaisten kivilajien fossiileja koskevat tutkimukset osoittavat, ett\u00e4 el\u00e4m\u00e4 sai todenn\u00e4k\u00f6isesti alkunsa noin 4 miljardia vuotta sitten, kun Maa oli viel\u00e4 hyvin nuori. Kukaan ei tied\u00e4, miten el\u00e4m\u00e4 alkoi Maassa. Useimmat tutkijat uskovat, ett\u00e4 se sai alkunsa nestem\u00e4isess\u00e4 vedess\u00e4. Mutta tapahtuiko t\u00e4m\u00e4 maanpinnan vesilammikoissa, maan alla vai merenpohjassa, jossa tulivuoren toiminta muodostaa kuumia l\u00e4hteit\u00e4?<\/p>\n<\/div>\n

Kokeet osoittavat, ett\u00e4 el\u00e4m\u00e4n kemialliset rakennuspalikat voivat muodostua avaruudessa tai maapallolla. Monet niist\u00e4 ovat varmasti saapuneet maapallolle putoavien meteoriittien ja komeettojen mukana. Jollain tavalla n\u00e4m\u00e4 yksinkertaiset \u2018orgaaniset\u2019 kemikaalit yhdistyiv\u00e4t muodostaen kehittyneempi\u00e4 molekyylej\u00e4. Sitten ne alkoivat monistua ja kasvaa.<\/p>\n

\"Dry
Kuiva maa<\/figcaption><\/figure>\n

Tied\u00e4mme kuitenkin, ett\u00e4 \u2013 kun el\u00e4m\u00e4 kerran p\u00e4\u00e4see vauhtiin \u2013 se on uskomattoman sitke\u00e4\u00e4. El\u00e4vi\u00e4 bakteereja on l\u00f6ydetty j\u00e4\u00e4tyneest\u00e4 Antarktikasta, kiehuvasta vedest\u00e4 ja jopa viiden kilometrin syvyydess\u00e4 maan alla olevista kivist\u00e4. Tied\u00e4mme my\u00f6s, ett\u00e4 t\u00e4llaiset organismit voivat selviyty\u00e4 vuosikausia avaruuden ankarissa olosuhteissa.<\/p>\n

Kun kasvit yleistyiv\u00e4t, ilmaan vapautui suuria m\u00e4\u00e4ri\u00e4 happea. Maasta tuli aurinkokuntamme ainoa planeetta, jolla on happirikas ilmakeh\u00e4. Etsim\u00e4ll\u00e4 happea muilta planeetoilta saatamme jonain p\u00e4iv\u00e4n\u00e4 l\u00f6yt\u00e4\u00e4 todisteita avaruusolentojen olemassaolosta.<\/p>","protected":false},"excerpt":{"rendered":"

Studies of fossils in ancient rocks tell us that life probably began about 4 billion years ago, when the Earth was very young. No one knows how life began on […]<\/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\/2003\/05\/dna_s_famous_double-helix_structure3\/17902899-2-eng-GB\/DNA_s_famous_double-helix_structure.jpg","esa_banner_description":"DNA's famous double-helix structure","esa_banner_credit":"ESA 2003. Illustration by Medialab.","esa_banner_licence":"ESA Standard Licence","esa_banner_detail_url":"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2003\/05\/DNA_s_famous_double-helix_structure3","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":[2],"panel":[],"language":[],"age":[],"duration":[],"resource_type":[],"audience":[],"wf_post_folders":[],"class_list":["post-1133","post","type-post","status-publish","format-standard","hentry","category-learn","category-our-universe","category-planets-and-moons","tag-background-article"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/1133","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=1133"}],"version-history":[{"count":5,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/1133\/revisions"}],"predecessor-version":[{"id":4865,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/1133\/revisions\/4865"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/media?parent=1133"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/categories?post=1133"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/tags?post=1133"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/panel?post=1133"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/language?post=1133"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/age?post=1133"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/duration?post=1133"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/resource_type?post=1133"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/audience?post=1133"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/wf_post_folders?post=1133"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}