{"id":887,"date":"2007-03-16T12:23:00","date_gmt":"2007-03-16T11:23:00","guid":{"rendered":"https:\/\/kids.esa.int\/radar_s_icy_echoes_on_mars\/"},"modified":"2026-10-08T00:33:23","modified_gmt":"2026-10-07T22:33:23","slug":"radar_s_icy_echoes_on_mars","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/fi\/radar_s_icy_echoes_on_mars\/","title":{"rendered":"Tutkan j\u00e4iset kaikueet Marsissa"},"content":{"rendered":"
\n

Marsia pidet\u00e4\u00e4n usein aavikoiden peitt\u00e4m\u00e4n\u00e4 kuivana maailmana. Kuitenkin, aivan kuten Maalla, Punaisella planeetallakin on kaksi suurta j\u00e4\u00e4peitett\u00e4 pohjois- ja etel\u00e4navalla. Jos ihmiset jonain p\u00e4iv\u00e4n\u00e4 asuvat Marsissa, on t\u00e4rke\u00e4\u00e4 tiet\u00e4\u00e4, kuinka paljon j\u00e4\u00e4tynytt\u00e4 vett\u00e4 n\u00e4iss\u00e4 j\u00e4\u00e4peitteiss\u00e4 on. Juuri t\u00e4t\u00e4 selvitt\u00e4\u00e4 ESA:n Mars Express -kiertoradalla olevan MARSIS-laite.<\/p>\n<\/div>\n

Etel\u00e4isen j\u00e4\u00e4peitteen paksuuden mittaamiseksi tutka l\u00e4hett\u00e4\u00e4 n\u00e4kym\u00e4tt\u00f6mi\u00e4 signaaleja kohti pintaa ja tallentaa niiden heijastumat. T\u00e4ll\u00e4 tavalla tutka pystyy \u2018n\u00e4kem\u00e4\u00e4n\u2019 kerrosten l\u00e4pi j\u00e4\u00e4n pohjaan asti. Napaa peitt\u00e4vist\u00e4 j\u00e4\u00e4- ja p\u00f6lykerrostumista on tehty yli 300 t\u00e4llaista \u2018leikkausta\u2019.<\/p>\n

\"Thickness
Marsin etel\u00e4navan kerrostumien paksuus<\/figcaption><\/figure>\n

Tied\u00e4mme nyt, ett\u00e4 etel\u00e4isen j\u00e4\u00e4peitteen paksuus on jopa 3,7 km. Jos kaikki j\u00e4\u00e4 sulaisi, koko planeetta peittyisi noin 11 metri\u00e4 syv\u00e4\u00e4n mereen. T\u00e4st\u00e4 valtavasta j\u00e4\u00e4peitteest\u00e4 huolimatta j\u00e4\u00e4n alla oleva kallioper\u00e4 ei ole painunut alas \u2013 mik\u00e4 osoittaa, ett\u00e4 se on j\u00e4ykemp\u00e4\u00e4 kuin maankuori.<\/p>\n

Pohjoisnavan j\u00e4\u00e4peitteest\u00e4 k\u00e4ynniss\u00e4 olevat tutkatutkimukset ovat osoittaneet, ett\u00e4 sen paksuus on noin 1,8 km. Molemmilla napa-alueilla esiintyv\u00e4t ohuet vesij\u00e4\u00e4- ja p\u00f6lykerrokset n\u00e4ytt\u00e4v\u00e4t johtuvan ilmaston kausittaisista ja pitk\u00e4aikaisista muutoksista. Vaikka napakupit sis\u00e4lt\u00e4v\u00e4t suurimman osan nykyisen Marsin tunnetusta vedest\u00e4, muutkin paikat planeetalla ovat saattaneet olla kaukaisessa menneisyydess\u00e4 riitt\u00e4v\u00e4n kosteita el\u00e4m\u00e4n yll\u00e4pit\u00e4miseksi.<\/p>","protected":false},"excerpt":{"rendered":"

Mars is often regarded as an arid world covered by deserts. However, like Earth, the Red Planet has two large ice caps at its north and south poles. If people […]<\/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\/2007\/03\/bright_lower_echo_from_mars_south-polar_layered_deposits2\/17901975-2-eng-GB\/Bright_lower_echo_from_Mars_south-polar_layered_deposits.jpg","esa_banner_description":"Bright lower echo from Mars\u2019 south-polar layered deposits","esa_banner_credit":"NASA\/JPL\/ASI\/ESA\/Univ. of Rome\/MOLA Science Team","esa_banner_licence":"ESA Standard Licence","esa_banner_detail_url":"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2007\/03\/Bright_lower_echo_from_Mars_south-polar_layered_deposits2","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-887","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\/887","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=887"}],"version-history":[{"count":4,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/887\/revisions"}],"predecessor-version":[{"id":4723,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/887\/revisions\/4723"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/media?parent=887"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/categories?post=887"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/tags?post=887"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/panel?post=887"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/language?post=887"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/age?post=887"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/duration?post=887"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/resource_type?post=887"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/audience?post=887"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/wf_post_folders?post=887"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}