{"id":12833,"date":"2021-07-20T21:36:44","date_gmt":"2021-07-20T21:36:44","guid":{"rendered":"https:\/\/www.lifescienceart.com\/?p=12833"},"modified":"2021-07-20T21:36:44","modified_gmt":"2021-07-20T21:36:44","slug":"sailing-stones-of-death-valley-enigma-unraveled","status":"publish","type":"post","link":"https:\/\/www.lifescienceart.com\/cs\/science\/earth-science\/sailing-stones-of-death-valley-enigma-unraveled\/","title":{"rendered":"Z\u00e1hadn\u00e9 plachetnice v \u00dadol\u00ed smrti"},"content":{"rendered":"<h2 class=\"wp-block-heading\">Z\u00e1hadn\u00e9 plachetnice v \u00dadol\u00ed smrti<\/h2>\n\n<h2 class=\"wp-block-heading\">\u00davod<\/h2>\n\n<p>V srdci n\u00e1rodn\u00edho parku \u00dadol\u00ed smrti le\u017e\u00ed geologick\u00e1 z\u00e1hada, kter\u00e1 po desetilet\u00ed fascinuje v\u011bdce: plachetnice. Tyto tajemn\u00e9 kameny se bez n\u00e1mahy klou\u017eou po vyprahl\u00e9m dn\u011b jezera Racetrack Playa a zanech\u00e1vaj\u00ed za sebou z\u00e1hadn\u00e9 stopy v p\u00edsku.<\/p>\n\n<h2 class=\"wp-block-heading\">Historick\u00e9 teorie<\/h2>\n\n<p>V pr\u016fb\u011bhu let se objevilo mnoho teori\u00ed, kter\u00e9 se sna\u017e\u00ed vysv\u011btlit pohyb plachetnic. N\u011bkte\u0159\u00ed navrhli, \u017ee by mohly b\u00fdt zodpov\u011bdn\u00e9 prachov\u00e9 v\u00edry nebo ob\u010dasn\u00e9 z\u00e1plavy. Jin\u00ed navrhli, \u017ee hnac\u00ed silou by mohly b\u00fdt ledov\u00e9 p\u0159\u00edkrovy nebo siln\u00e9 v\u011btry.<\/p>\n\n<h2 class=\"wp-block-heading\">Experiment u kuchy\u0148sk\u00e9ho stolu<\/h2>\n\n<p>V roce 2006 narazil planet\u00e1rn\u00ed v\u011bdec Ralph Lorenz na plachetnice, kdy\u017e v \u00dadol\u00ed smrti instaloval meteorologick\u00e9 stanice. Ohromen jejich zvl\u00e1\u0161tn\u00edm chov\u00e1n\u00edm navrhl jednoduch\u00fd experiment u sv\u00e9ho kuchy\u0148sk\u00e9ho stolu. Lorenz um\u00edstil mal\u00fd k\u00e1men do n\u00e1doby s vodou a zmrazil ho. Kdy\u017e hybrid k\u00e1men-led obr\u00e1til vzh\u016fru nohama a nechal ho plavat v misce s vodou a p\u00edskem, zjistil, \u017ee m\u016f\u017ee kamenem pohybovat po misce, kdy\u017e bude jemn\u011b foukat na led.<\/p>\n\n<h2 class=\"wp-block-heading\">Model plovouc\u00ed ledov\u00e9 kry<\/h2>\n\n<p>Na z\u00e1klad\u011b sv\u00e9ho experimentu u kuchy\u0148sk\u00e9ho stolu navrhl Lorenz model plovouc\u00ed ledov\u00e9 kry. Podle t\u00e9to teorie se kolem kamene vytvo\u0159\u00ed tenk\u00e1 vrstva ledu, d\u00edky n\u00ed\u017e bude plavat. Hladina kapaliny se m\u011bn\u00ed a zved\u00e1 k\u00e1men z bahna. V\u00fdsledn\u00e1 plovouc\u00ed ledov\u00e1 kra funguje jako mal\u00e1 lo\u010f s k\u00fdlem sm\u011b\u0159uj\u00edc\u00edm dol\u016f, kter\u00e1 p\u0159i pohybu ledov\u00e9 kry vyhloub\u00ed stopu v m\u011bkk\u00e9m sedimentu.<\/p>\n\n<h2 class=\"wp-block-heading\">Podp\u016frn\u00e9 d\u016fkazy<\/h2>\n\n<p>Model plovouc\u00ed ledov\u00e9 kry vysv\u011btluje n\u011bkolik kl\u00ed\u010dov\u00fdch pozorov\u00e1n\u00ed o plachetnic\u00edch:<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>Paraleln\u00ed a neparaleln\u00ed stopy:<\/strong> Lorenz\u016fv model vysv\u011btluje jak paraleln\u00ed, tak neparaleln\u00ed stopy, kter\u00e9 kameny zanech\u00e1vaj\u00ed. Paraleln\u00ed stopy nazna\u010duj\u00ed, \u017ee kameny byly zapu\u0161t\u011bny do stejn\u00e9 ledov\u00e9 kry, zat\u00edmco neparaleln\u00ed stopy nazna\u010duj\u00ed, \u017ee se kameny pohybovaly nez\u00e1visle.<\/li>\n<li><strong>Ledov\u00e9 l\u00edmce:<\/strong> V\u011bdci pozorovali ledov\u00e9 l\u00edmce kolem plachetnic, co\u017e podporuje my\u0161lenku, \u017ee led hraje v jejich pohybu z\u00e1sadn\u00ed roli.<\/li>\n<li><strong>Rychlosti v\u011btru:<\/strong> V\u00fdpo\u010dty ukazuj\u00ed, \u017ee rychlosti v\u011btru pot\u0159ebn\u00e9 k pohybu plachetnic podle jin\u00fdch model\u016f by byly ne\u00fam\u011brn\u011b vysok\u00e9. Model plovouc\u00ed ledov\u00e9 kry v\u0161ak nevy\u017eaduje tak extr\u00e9mn\u00ed rychlosti v\u011btru.<\/li>\n<\/ul>\n\n<h2 class=\"wp-block-heading\">Trval\u00e9 tajemstv\u00ed<\/h2>\n\n<p>P\u0159es p\u0159esv\u011bd\u010div\u00e9 d\u016fkazy podporuj\u00edc\u00ed model plovouc\u00ed ledov\u00e9 kry z\u00e1hada plachetnic p\u0159etrv\u00e1v\u00e1. Str\u00e1\u017ece parku Alan Van Valkenburg poznamen\u00e1v\u00e1, \u017ee mnoho n\u00e1v\u0161t\u011bvn\u00edk\u016f Racetrack Playa d\u00e1v\u00e1 p\u0159ednost tomu, aby si zachovali pocit tajemstv\u00ed kolem kamen\u016f. Nach\u00e1zej\u00ed \u00fat\u011bchu v nezodpov\u011bzen\u00fdch ot\u00e1zk\u00e1ch a \u00fachvatn\u00e9 pod\u00edvan\u00e9 na tyto tajemn\u00e9 kameny klouzaj\u00edc\u00ed po pou\u0161tn\u00ed krajin\u011b.<\/p>\n\n<h2 class=\"wp-block-heading\">Nad\u010dasovost kamen\u016f<\/h2>\n\n<p>Plachetnice se pohybuj\u00ed po tis\u00edcilet\u00ed, jejich cesty jsou vyryty do dna playa jako starov\u011bk\u00e9 hieroglyfy. Jak lidsk\u00e9 civilizace povst\u00e1vaj\u00ed a padaj\u00ed a m\u011bsta jsou stav\u011bna a opu\u0161t\u011bna, kameny budou pokra\u010dovat ve sv\u00e9 v\u011b\u010dn\u00e9 cest\u011b a vytes\u00e1vat sv\u00e9 z\u00e1hadn\u00e9 stopy do tvrd\u00e9, rovn\u00e9 zem\u011b. Zmrazen\u00e9 v ledu a popostrkovan\u00e9 i t\u00edm nejmen\u0161\u00edm v\u00e1nkem stoj\u00ed jako sv\u011bdectv\u00ed o trval\u00e9 s\u00edle p\u0159\u00edrody a bezb\u0159eh\u00fdch divech p\u0159\u00edrodn\u00edho sv\u011bta.<\/p>","protected":false},"excerpt":{"rendered":"<p>Z\u00e1hadn\u00e9 plachetnice v \u00dadol\u00ed smrti \u00davod V srdci n\u00e1rodn\u00edho parku \u00dadol\u00ed smrti le\u017e\u00ed geologick\u00e1 z\u00e1hada, kter\u00e1 po desetilet\u00ed fascinuje v\u011bdce: plachetnice. Tyto tajemn\u00e9 kameny se bez n\u00e1mahy klou\u017eou po vyprahl\u00e9m&hellip;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[212],"tags":[207,17344,252,16437,319],"class_list":["post-12833","post","type-post","status-publish","format-standard","hentry","category-earth-science","tag-geology","tag-sailing-stones","tag-nature","tag-death-valley","tag-mystery"],"_links":{"self":[{"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/posts\/12833","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/comments?post=12833"}],"version-history":[{"count":1,"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/posts\/12833\/revisions"}],"predecessor-version":[{"id":12834,"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/posts\/12833\/revisions\/12834"}],"wp:attachment":[{"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/media?parent=12833"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/categories?post=12833"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/tags?post=12833"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}