{"id":1138,"date":"2004-11-16T10:43:00","date_gmt":"2004-11-16T09:43:00","guid":{"rendered":"https:\/\/kids.esa.int\/asteroid_families\/"},"modified":"2026-10-08T00:36:26","modified_gmt":"2026-10-07T22:36:26","slug":"asteroid_families","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/fi\/asteroid_families\/","title":{"rendered":"Asteroidien perheet"},"content":{"rendered":"
\n

Ceresin halkaisijan tiedet\u00e4\u00e4n nyky\u00e4\u00e4n olevan noin 940 km \u2013 noin nelj\u00e4nnes (yksi nelj\u00e4sosa) Maan Kuun koosta. Sen osuus on kuitenkin yli nelj\u00e4nnes kaikkien asteroidien kokonaispainosta.<\/p>\n<\/div>\n

Viel\u00e4 16 asteroidia on halkaisijaltaan yli 240 km. Suurin osa asteroideista on kuitenkin kivi\u00e4 ja lohkareita, joiden halkaisija on vain muutama metri. Jos ne kaikki puristettaisiin yhteen kappaleeksi, se olisi silti pienempi kuin Kuu. Jotkut asteroidit ovat kivisi\u00e4, toiset taas koostuvat metalleista, kuten raudasta ja nikkelist\u00e4. Suurin osa on v\u00e4rilt\u00e4\u00e4n mustanruskeita ja sis\u00e4lt\u00e4\u00e4 runsaasti hiilt\u00e4.<\/p>\n

Monet asteroidit kuuluvat perheisiin. Jokaisella perheell\u00e4 on sama v\u00e4ri, ja ne n\u00e4ytt\u00e4v\u00e4t koostuvan samoista aineista. Ne liikkuvat my\u00f6s l\u00e4hell\u00e4 toisiaan p\u00e4\u00e4vy\u00f6n eri osissa. Yksi suurimmista n\u00e4ist\u00e4 on Flora-perhe, johon kuuluu noin 400 tunnettua j\u00e4sent\u00e4.<\/p>\n

Asteroideja l\u00f6ytyy my\u00f6s p\u00e4\u00e4vy\u00f6hykkeen ulkopuolelta. Ne ovat joutuneet pois alkuper\u00e4iselt\u00e4 paikaltaan Jupiterin voimakkaan painovoiman tai muiden asteroidien kanssa tapahtuneiden t\u00f6rm\u00e4ysten seurauksena. Jotkut niist\u00e4 ovat muuttuneet j\u00e4ttil\u00e4isplaneetan kuiksi. Satoja tuhansia asteroideja \u2013 joista osa on suuria \u2013 lent\u00e4\u00e4 l\u00e4hell\u00e4 Maata.<\/p>","protected":false},"excerpt":{"rendered":"

Ceres is now known to have a width of about 940 km – about one quarter (one fourth) the size of Earth’s Moon. But it accounts for more than one […]<\/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\/2002\/04\/typical_orbits_for_inner_solar_system_asteroids2\/17865268-3-eng-GB\/Typical_orbits_for_inner_solar_system_asteroids.jpg","esa_banner_description":"Typical orbits for inner solar system asteroids","esa_banner_credit":"ESA 2002. Illustration by Medialab","esa_banner_licence":"ESA Standard Licence","esa_banner_detail_url":"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2002\/04\/Typical_orbits_for_inner_solar_system_asteroids2","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":[46,10,11],"tags":[2],"panel":[],"language":[],"age":[],"duration":[],"resource_type":[],"audience":[],"wf_post_folders":[],"class_list":["post-1138","post","type-post","status-publish","format-standard","hentry","category-comets-and-meteors","category-learn","category-our-universe","tag-background-article"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/1138","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=1138"}],"version-history":[{"count":1,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/1138\/revisions"}],"predecessor-version":[{"id":2281,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/1138\/revisions\/2281"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/media?parent=1138"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/categories?post=1138"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/tags?post=1138"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/panel?post=1138"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/language?post=1138"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/age?post=1138"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/duration?post=1138"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/resource_type?post=1138"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/audience?post=1138"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/wf_post_folders?post=1138"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}