{"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\/pt\/telltale_signs\/","title":{"rendered":"Sinais reveladores"},"content":{"rendered":"
\n

A Terra \u00e9 o \u00fanico lugar que conhecemos onde existe vida. O que a torna t\u00e3o especial? Um fator fundamental \u00e9 a presen\u00e7a de \u00e1gua l\u00edquida. A vida na Terra parece ter tido in\u00edcio em po\u00e7as ou mares. Nenhuma forma de vida no nosso planeta consegue sobreviver sem \u00e1gua.<\/p>\n<\/div>\n

A Terra \u00e9 o \u00fanico lugar no nosso Sistema Solar com grandes oceanos na sua superf\u00edcie. Isto deve-se ao facto de se situar na zona \u2018Goldilocks\u2019.<\/p>\n

V\u00e9nus est\u00e1 demasiado perto do Sol e \u00e9 demasiado quente. Marte est\u00e1 demasiado longe e \u00e9 demasiado frio. A Terra est\u00e1 \u00e0 dist\u00e2ncia certa e tem a temperatura certa.<\/p>\n

Ser\u00e1 que existem \u2018Terras\u2019 a orbitar outras estrelas? Como \u00e9 que as reconhecer\u00edamos? A primeira coisa a fazer \u00e9 medir a temperatura de um planeta. Dever\u00e1 tamb\u00e9m haver ind\u00edcios de que a \u00e1gua \u00e9 abundante.<\/p>\n

Ent\u00e3o, temos de procurar gases como o oxig\u00e9nio e o metano. Estes gases s\u00e3o libertados para a atmosfera por seres vivos.<\/p>\n

As futuras miss\u00f5es ir\u00e3o procurar estes \u2018biomarcadores\u2019 em milhares de sistemas estelares. Embora n\u00e3o detetem oxig\u00e9nio diretamente, ir\u00e3o \u2018detetar\u2019 ozono, uma forma de oxig\u00e9nio. Ir\u00e3o tamb\u00e9m detetar di\u00f3xido de carbono, \u00e1gua e, em certos casos, metano.<\/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\/pt\/wp-json\/wp\/v2\/posts\/953","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kids.esa.int\/pt\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kids.esa.int\/pt\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/pt\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/pt\/wp-json\/wp\/v2\/comments?post=953"}],"version-history":[{"count":1,"href":"https:\/\/kids.esa.int\/pt\/wp-json\/wp\/v2\/posts\/953\/revisions"}],"predecessor-version":[{"id":2096,"href":"https:\/\/kids.esa.int\/pt\/wp-json\/wp\/v2\/posts\/953\/revisions\/2096"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/pt\/wp-json\/wp\/v2\/media?parent=953"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/pt\/wp-json\/wp\/v2\/categories?post=953"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/pt\/wp-json\/wp\/v2\/tags?post=953"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/pt\/wp-json\/wp\/v2\/panel?post=953"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/pt\/wp-json\/wp\/v2\/language?post=953"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/pt\/wp-json\/wp\/v2\/age?post=953"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/pt\/wp-json\/wp\/v2\/duration?post=953"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/pt\/wp-json\/wp\/v2\/resource_type?post=953"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/pt\/wp-json\/wp\/v2\/audience?post=953"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/pt\/wp-json\/wp\/v2\/wf_post_folders?post=953"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}