{"id":953,"date":"2004-11-19T08:31:00","date_gmt":"2004-11-19T07:31:00","guid":{"rendered":"https:\/\/kids.esa.int\/telltale_signs\/"},"modified":"2026-10-08T00:34:10","modified_gmt":"2026-10-07T22:34:10","slug":"telltale_signs","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/da\/telltale_signs\/","title":{"rendered":"Tydelige tegn"},"content":{"rendered":"
\n

Jorden er det eneste sted, vi kender til, hvor der findes liv. Hvad g\u00f8r den s\u00e5 speciel? En afg\u00f8rende faktor er tilstedev\u00e6relsen af flydende vand. Livet p\u00e5 Jorden synes at have opst\u00e5et i vandhuller eller havene. Intet liv p\u00e5 vores planet kan overleve uden vand.<\/p>\n<\/div>\n

Jorden er det eneste sted i vores solsystem, hvor der findes store oceaner p\u00e5 overfladen. Det skyldes, at den befinder sig i \u2018Goldilocks\u2019-zonen.<\/p>\n

Venus ligger for t\u00e6t p\u00e5 Solen og er for varm. Mars ligger for langt v\u00e6k og er for kold. Jorden ligger i netop den rette afstand og har den rette temperatur.<\/p>\n

Kunne der v\u00e6re \u2018Jord-lignende planeter\u2019, der kredser om andre stjerner? Hvordan ville vi kunne genkende dem? Det f\u00f8rste, man skal g\u00f8re, er at m\u00e5le, hvor varm eller kold en planet er. Der b\u00f8r ogs\u00e5 v\u00e6re tegn p\u00e5, at der findes rigelige m\u00e6ngder vand.<\/p>\n

S\u00e5 m\u00e5 vi lede efter gasser som ilt og metan. Disse gasser udskilles i luften af levende v\u00e6sener.<\/p>\n

Fremtidige missioner vil lede efter disse \u2018biomark\u00f8rer\u2019 i tusindvis af stjerne-planet-systemer. Selvom de ikke vil kunne p\u00e5vise ilt direkte, vil de kunne \u2018se\u2019 ozon, som er en form for ilt. De vil ogs\u00e5 kunne se kuldioxid, vand og, i visse tilf\u00e6lde, metan.<\/p>","protected":false},"excerpt":{"rendered":"

Earth is the only place we know that supports life. What makes it so special? One key factor is the presence of liquid water. Life on Earth seems to have […]<\/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\/01\/planet_earth_as_seen_by_the_apollo_17_astronauts2\/17863973-3-eng-GB\/Planet_Earth_as_seen_by_the_Apollo_17_astronauts.jpg","esa_banner_description":"Planet Earth as seen by the Apollo 17 astronauts","esa_banner_credit":"NASA","esa_banner_licence":"ESA Standard Licence","esa_banner_detail_url":"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2002\/01\/Planet_Earth_as_seen_by_the_Apollo_17_astronauts2","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":[14,10,13],"tags":[2],"panel":[],"language":[],"age":[],"duration":[],"resource_type":[],"audience":[],"wf_post_folders":[],"class_list":["post-953","post","type-post","status-publish","format-standard","hentry","category-are-we-alone","category-learn","category-life-in-space","tag-background-article"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/posts\/953","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/comments?post=953"}],"version-history":[{"count":1,"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/posts\/953\/revisions"}],"predecessor-version":[{"id":2096,"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/posts\/953\/revisions\/2096"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/media?parent=953"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/categories?post=953"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/tags?post=953"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/panel?post=953"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/language?post=953"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/age?post=953"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/duration?post=953"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/resource_type?post=953"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/audience?post=953"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/da\/wp-json\/wp\/v2\/wf_post_folders?post=953"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}