Co se stalo se Saturnov\u00fdm m\u011bs\u00edcem Iapetusem? Rozs\u00e1hl\u00e9 \u010d\u00e1sti tohoto podivn\u00e9ho sv\u011bta jsou tmav\u00e9 jako uhl\u00ed, zat\u00edmco jin\u00e9 jsou sv\u011btl\u00e9 jako sn\u00edh. Abychom l\u00e9pe porozum\u011bli tomuto neobvykle zbarven\u00e9mu m\u011bs\u00edci, NASA v roce 2007 na\u0159\u00eddila robotick\u00e9 sond\u011b Cassini, kter\u00e1 tehdy ob\u00edhala kolem Saturnu, aby se p\u0159ibl\u00ed\u017eila na vzd\u00e1lenost 2 000 kilometr\u016f. Na sn\u00edmku, po\u0159\u00edzen\u00e9m ze vzd\u00e1lenosti asi 75 000 kilometr\u016f, je zachycena polokoule Iapetu, kter\u00e1 je v\u017edy v pozad\u00ed. Velk\u00fd impaktn\u00ed kr\u00e1ter viditeln\u00fd na jihu m\u00e1 pr\u016fm\u011br 500 kilometr\u016f a zd\u00e1 se, \u017ee p\u0159ekr\u00fdv\u00e1 star\u0161\u00ed kr\u00e1ter podobn\u00e9 velikosti. Je patrn\u00e9, \u017ee tmav\u00fd materi\u00e1l st\u00e1le v\u00edce pokr\u00fdv\u00e1 nejv\u00fdchodn\u011bj\u0161\u00ed \u010d\u00e1st Iapetu a ztmavuje jak kr\u00e1tery, tak vyv\u00fd\u0161eniny. Jednou z hlavn\u00edch hypot\u00e9z je, \u017ee tento tmav\u00fd materi\u00e1l tvo\u0159\u00ed p\u0159ev\u00e1\u017en\u011b p\u016fda bohat\u00e1 na uhl\u00edk, kter\u00e1 zbyla po sublimaci relativn\u011b tepl\u00e9ho, ale zne\u010di\u0161t\u011bn\u00e9ho ledu. P\u016fvodn\u00ed vrstva tohoto tmav\u00e9ho materi\u00e1lu mohla b\u00fdt v podstat\u011b nanesena akrec\u00ed \u00falomk\u016f uvoln\u011bn\u00fdch dopady meteorit\u016f z jin\u00fdch m\u011bs\u00edc\u016f. M\u011bs\u00edc jako skl\u00e1da\u010dka: Astronomick\u00e1 h\u00e1danka dne<\/p>\n
<\/p>\n
**Credit**: NASA<\/p>\n","protected":false},"excerpt":{"rendered":"
Co se stalo se Saturnov\u00fdm m\u011bs\u00edcem Iapetusem? Rozs\u00e1hl\u00e9 \u010d\u00e1sti tohoto podivn\u00e9ho sv\u011bta jsou tmav\u00e9 jako uhl\u00ed, zat\u00edmco jin\u00e9 jsou sv\u011btl\u00e9 jako sn\u00edh. Abychom l\u00e9pe porozum\u011bli tomuto neobvykle zbarven\u00e9mu m\u011bs\u00edci, NASA […]<\/p>\n","protected":false},"author":1,"featured_media":3938,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-3937","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-nasa"],"_links":{"self":[{"href":"https:\/\/astrohodonin.cz\/index.php\/wp-json\/wp\/v2\/posts\/3937","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/astrohodonin.cz\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/astrohodonin.cz\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/astrohodonin.cz\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/astrohodonin.cz\/index.php\/wp-json\/wp\/v2\/comments?post=3937"}],"version-history":[{"count":0,"href":"https:\/\/astrohodonin.cz\/index.php\/wp-json\/wp\/v2\/posts\/3937\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/astrohodonin.cz\/index.php\/wp-json\/wp\/v2\/media\/3938"}],"wp:attachment":[{"href":"https:\/\/astrohodonin.cz\/index.php\/wp-json\/wp\/v2\/media?parent=3937"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/astrohodonin.cz\/index.php\/wp-json\/wp\/v2\/categories?post=3937"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/astrohodonin.cz\/index.php\/wp-json\/wp\/v2\/tags?post=3937"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}