{"id":921,"date":"2004-11-15T16:12:00","date_gmt":"2004-11-15T15:12:00","guid":{"rendered":"https:\/\/kids.esa.int\/phobos_and_deimos\/"},"modified":"2026-10-08T00:33:48","modified_gmt":"2026-10-07T22:33:48","slug":"phobos_and_deimos","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/sv\/phobos_and_deimos\/","title":{"rendered":"Phobos och Deimos"},"content":{"rendered":"
\n

\u00c5r 1877 uppt\u00e4ckte den amerikanske astronomen Asaph Hall tv\u00e5 sm\u00e5 m\u00e5nar som kretsade kring planeten Mars. De fick namnen Phobos (R\u00e4dsla) och Deimos (Panik). Mer \u00e4n 130 \u00e5r senare f\u00f6rs\u00f6ker forskarna fortfarande att l\u00f6sa mysterierna kring dessa m\u00e5nar.<\/p>\n<\/div>\n

Det kan vara asteroider \u2013 sm\u00e5 stenar som blivit kvar fr\u00e5n planeternas tillkomst \u2013 som f\u00e5ngats in av Mars.<\/p>\n

B\u00e5da m\u00e5narna \u00e4r svartare \u00e4n kol och ser ut som mosade potatisar. Phobos \u00e4r 27 km i diameter p\u00e5 det bredaste st\u00e4llet och har en stor nedslagskrater p\u00e5 ena sidan. Den kretsar runt Mars tre g\u00e5nger under en marsdag.<\/p>\n

Deimos \u00e4r \u00e4nnu mindre \u2013 en av de minsta m\u00e5narna i solsystemet. Den ligger l\u00e4ngre bort fr\u00e5n Mars, s\u00e5 varje varv runt planeten tar drygt en dag.<\/p>\n

Deras ringa storlek inneb\u00e4r att tyngdkraften p\u00e5 b\u00e5da m\u00e5narna \u00e4r mycket svag. En astronaut som st\u00e5r p\u00e5 Phobos skulle uppleva en 1 000 g\u00e5nger svagare tyngdkraft \u00e4n p\u00e5 jorden. Stora hopp skulle kunna leda till att astronauten flyger iv\u00e4g ut i rymden!<\/p>\n

N\u00e4rpassager av ESA:s rymdsond Mars Express har gett ledtr\u00e5dar om vad dessa planeter best\u00e5r av och varifr\u00e5n de kommer.<\/p>\n

Mars Express \u00e4r den enda rymdsonden som f\u00f6r n\u00e4rvarande \u00e4r i drift runt den r\u00f6da planeten och som befinner sig i en starkt elliptisk (\u00e4ggformad) bana. Denna bana leder den \u00f6ver Phobos bana, vilket g\u00f6r det m\u00f6jligt att se alla sidor av den lilla m\u00e5nen. (Precis som jordens m\u00e5ne v\u00e4nder Phobos alltid samma sida mot den n\u00e4rliggande planeten.) Mellan den 23 juli och den 15 september 2008 genomf\u00f6rde Mars Express \u00e5tta f\u00f6rbiflygningar av Phobos, d\u00e4r den svepte f\u00f6rbi p\u00e5 avst\u00e5nd som varierade fr\u00e5n 4 500 km till endast 93 km.<\/p>\n

N\u00e4rbilder visar att Phobos, den st\u00f6rre m\u00e5nen, \u00e4r en potatisformad rymdsten som m\u00e4ter endast 27 km \u00d7 22 km \u00d7 19 km. Den \u00e4r mycket m\u00f6rk \u2013 svartare \u00e4n kol \u2013 och full av kratrar. Genom att noggrant f\u00f6lja hur Phobos p\u00e5verkar Mars Express vid varje f\u00f6rbiflygning har forskarna kommit fram till att m\u00e5nen inte har s\u00e4rskilt h\u00f6g densitet. Den \u00e4r med st\u00f6rsta sannolikhet en \u2018stenh\u00f6g\u2019 \u2013 best\u00e5ende av m\u00e5nga stenblock som h\u00e5lls samman av gravitationen \u2013 snarare \u00e4n ett enda, sammanh\u00e4ngande objekt.<\/p>\n

Forskning kring Mars Express tyder p\u00e5 att Phobos och Deimos en g\u00e5ng kan ha varit asteroider som kretsade kring solen mellan Mars och Jupiter. Ingen kan dock \u00e4nnu f\u00f6rklara hur de f\u00e5ngades in av Mars och hamnade i \u2018normala\u2019 banor ovanf\u00f6r planetens ekvator.<\/p>","protected":false},"excerpt":{"rendered":"

In 1877, the American astronomer Asaph Hall discovered two small moons circling the planet Mars. They were named Phobos (Fear) and Deimos (Panic). More than 130 years later, scientists are […]<\/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\/2004\/11\/phobos_in_colour_close-up2\/17881549-2-eng-GB\/Phobos_in_colour_close-up.jpg","esa_banner_description":"Phobos in colour, close-up","esa_banner_credit":"ESA\/DLR\/FU Berlin (G. Neukum)","esa_banner_licence":"ESA Standard Licence","esa_banner_detail_url":"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2004\/11\/Phobos_in_colour_close-up2","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-921","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\/sv\/wp-json\/wp\/v2\/posts\/921","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kids.esa.int\/sv\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kids.esa.int\/sv\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/sv\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/sv\/wp-json\/wp\/v2\/comments?post=921"}],"version-history":[{"count":1,"href":"https:\/\/kids.esa.int\/sv\/wp-json\/wp\/v2\/posts\/921\/revisions"}],"predecessor-version":[{"id":2064,"href":"https:\/\/kids.esa.int\/sv\/wp-json\/wp\/v2\/posts\/921\/revisions\/2064"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/sv\/wp-json\/wp\/v2\/media?parent=921"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/sv\/wp-json\/wp\/v2\/categories?post=921"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/sv\/wp-json\/wp\/v2\/tags?post=921"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/sv\/wp-json\/wp\/v2\/panel?post=921"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/sv\/wp-json\/wp\/v2\/language?post=921"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/sv\/wp-json\/wp\/v2\/age?post=921"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/sv\/wp-json\/wp\/v2\/duration?post=921"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/sv\/wp-json\/wp\/v2\/resource_type?post=921"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/sv\/wp-json\/wp\/v2\/audience?post=921"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/sv\/wp-json\/wp\/v2\/wf_post_folders?post=921"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}