{"id":897,"date":"2008-06-17T09:24:00","date_gmt":"2008-06-17T07:24:00","guid":{"rendered":"https:\/\/kids.esa.int\/goce_esa_s_gravity_explorer\/"},"modified":"2026-10-08T00:33:31","modified_gmt":"2026-10-07T22:33:31","slug":"goce_esa_s_gravity_explorer","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/fi\/goce_esa_s_gravity_explorer\/","title":{"rendered":"GOCE \u2013 ESA:n Gravity Explorer"},"content":{"rendered":"
\n

Tiesitk\u00f6, ett\u00e4 painosi vaihtelee hieman sen mukaan, miss\u00e4 asut? T\u00e4m\u00e4 johtuu siit\u00e4, ett\u00e4 maapallon painovoiman voimakkuus vaihtelee paikasta toiseen. ESA:n Gravity field and steady-state Ocean Circulation Explorer (GOCE) -satelliitti mittaa parhaillaan, kuinka paljon painovoima tarkalleen ottaen vaihtelee.<\/p>\n<\/div>\n

Maaliskuussa 2009 laukaisun saanut GOCE on ensimm\u00e4inen ESA:n Earth Explorer -ohjelman avaruuslento. Sen teht\u00e4v\u00e4n\u00e4 on tuottaa t\u00e4h\u00e4n menness\u00e4 parasta tietoa maapallon \u2018painovoimakent\u00e4st\u00e4\u2019.<\/p>\n

Painovoima on voima, joka pit\u00e4\u00e4 meid\u00e4t kaikki maan pinnalla. Ilman sit\u00e4 kaikki (ja kaikki), mit\u00e4 ei olisi kiinnitetty paikoilleen, leijuisi avaruuteen. Maan painovoima vaihtelee kuitenkin paikasta toiseen. T\u00e4m\u00e4 johtuu osittain siit\u00e4, ett\u00e4 maapallo ei ole t\u00e4ysin py\u00f6re\u00e4 \u2013 se on hieman litistynyt navoilla. Painovoimaan vaikuttavat my\u00f6s korkeat vuoret, syv\u00e4t meren syv\u00e4nteet sek\u00e4 kalliokerrosten paksuus ja tiheys.<\/p>\n

\"Earth's
GOCE:n kuvaama maapallon geoidi<\/figcaption><\/figure>\n

Pienten painovoiman vaihteluiden mittaaminen on eritt\u00e4in vaikeaa, etenkin avaruudesta k\u00e4sin. Jotta GOCE voisi havaita mahdollisimman voimakkaan painovoimasignaalin, se kiert\u00e4\u00e4 matalalla, 255 km:n korkeudella maan yl\u00e4puolella. Kun se lent\u00e4\u00e4 alueiden yli, joissa painovoima on voimakkaampaa tai heikompaa, avaruusalus heilahtaa yl\u00f6s ja alas, ja sen mittalaitteet rekister\u00f6iv\u00e4t n\u00e4m\u00e4 muutokset sen reitin varrella.<\/p>\n

Nuolenmuotoinen GOCE on my\u00f6s eritt\u00e4in vakaa, sill\u00e4 siin\u00e4 ei ole lainkaan liikkuvia osia, joita usein n\u00e4hd\u00e4\u00e4n muissa avaruusaluksissa. Edistyksellinen asennonhallintaj\u00e4rjestelm\u00e4 varmistaa, ett\u00e4 satelliitin liikkeet eiv\u00e4t vaikuta sen painovoimamittauksiin.<\/p>\n

Miksi painovoiman tarkka mittaaminen on t\u00e4rke\u00e4\u00e4? GOCE-satelliitin tuottamaa dataa k\u00e4ytet\u00e4\u00e4n merivirtausten, merenpinnan muutosten, maanpinnan korkeuden ja vuorten juurien syvyyden tutkimiseen. Sill\u00e4 on my\u00f6s lukuisia k\u00e4yt\u00e4nn\u00f6n sovelluksia, esimerkiksi rakennusalalla.<\/p>","protected":false},"excerpt":{"rendered":"

Did you know that your weight is slightly different, depending on where you live? This is because the pull of Earth\u2019s gravity varies from place to place. Precisely how much […]<\/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\/2008\/03\/sunny_side_of_goce3\/17887395-2-eng-GB\/Sunny_side_of_GOCE.jpg","esa_banner_description":"Sunny side of GOCE","esa_banner_credit":"ESA\u2013AOES-Medialab","esa_banner_licence":"ESA Standard Licence","esa_banner_detail_url":"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2008\/03\/Sunny_side_of_GOCE3","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":[42,10,66],"tags":[],"panel":[],"language":[],"age":[],"duration":[],"resource_type":[],"audience":[],"wf_post_folders":[],"class_list":["post-897","post","type-post","status-publish","format-standard","hentry","category-earth","category-learn","category-water-world"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/897","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=897"}],"version-history":[{"count":5,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/897\/revisions"}],"predecessor-version":[{"id":4727,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/897\/revisions\/4727"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/media?parent=897"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/categories?post=897"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/tags?post=897"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/panel?post=897"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/language?post=897"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/age?post=897"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/duration?post=897"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/resource_type?post=897"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/audience?post=897"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/wf_post_folders?post=897"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}