{"id":2329,"date":"2024-03-07T00:37:10","date_gmt":"2024-03-06T23:37:10","guid":{"rendered":"https:\/\/www.zahadyazajimavosti.cz\/?p=2329"},"modified":"2024-05-11T18:12:41","modified_gmt":"2024-05-11T16:12:41","slug":"co-zpusobil-pad-komety","status":"publish","type":"post","link":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/2024\/03\/07\/co-zpusobil-pad-komety\/","title":{"rendered":"Co zp\u016fsobil p\u00e1d komety"},"content":{"rendered":"

Lid\u00e9, kte\u0159\u00ed ob\u00fdvali Severn\u00ed Ameriku, byli vyhlazeni kometou, kter\u00e1 narazila do Zem\u011b p\u0159ed 13.000 lety<\/strong>
\nV dlouhodob\u00e9m sporu o tom, co zahubilo americk\u00e9 domorodce, zv\u00edt\u011bzili zast\u00e1nci hypot\u00e9zy p\u00e1du komety. Obdr\u017eeli toti\u017e nov\u00e9 d\u016fkazy. P\u0159edstavili je badatel\u00e9 z Harvardsk\u00e9 University, pod veden\u00edm Michaela Petaeva. (1)<\/p>\n

Ve vzorc\u00edch ledu, z\u00edskan\u00fdch v Gr\u00f3nsku v\u011bdci objevili platinov\u00fd prach – velmi hust\u00e9 usazeniny, kter\u00e9 vznikly p\u0159ed 12.890 lety.<\/p>\n

Platina byla kosmick\u00e9ho p\u016fvodu. A z toho vyplynul i z\u00e1v\u011br, \u017ee jej\u00edm zdrojem byla kometa.<\/p>\n

\"\"<\/p>\n

Obr. Tyto kuli\u010dky vznikly v d\u016fsledku n\u00e1razu komety p\u0159ed 13000 lety. Foto: University of California<\/em><\/p>\n

Shodou okolnost\u00ed pr\u00e1v\u011b p\u0159ed 12.900 lety na severn\u00ed polokouli za\u010dalo n\u00e1hl\u00e9 chladn\u00e9 po\u010das\u00ed.<\/p>\n

V\u011bdci samoz\u0159ejm\u011b podez\u0159\u00edvali kometu, jej\u00ed\u017e p\u00e1d vyvrhl miliardy tun prachu a vody do atmosf\u00e9ry.<\/p>\n

Podle Petaeva ochlazen\u00ed trvalo asi 500 let. To tak\u00e9 zni\u010dilo domorod\u00e9 Ameri\u010dany – z\u00e1stupce kultury Clovis (2). Domorodci zmizeli p\u0159ed 13.000 lety, spolu s velk\u00fdmi zv\u00ed\u0159aty, kter\u00e9 lovili – mamuty, mastodonty, srstnat\u00e9 nosoro\u017ece, \u0161avlozub\u00e9 tygry, jeskynn\u00ed medv\u011bdy. V\u0161ichni umrzli.<\/p>\n

Prvn\u00ed v\u011bdci, kte\u0159\u00ed vyslovili hypot\u00e9zu o komet\u011b, kter\u00e1 zas\u00e1hla Severn\u00ed Ameriku v dob\u011b kamenn\u00e9, byli v\u00fdzkumn\u00edci v \u010dele s Jamesem P. Kennettem (3) z University v Californii v Santa Barba\u0159e, a to p\u0159ed \u0161esti lety.<\/p>\n

V roce 2007 na\u0161li lo\u017eiska mikroskopick\u00fdch kuli\u010dek, kter\u00e9 vznikly v d\u016fsledku oh\u0159evu kamene na vysokou teplotu – asi 2000\u00b0 C, za vysok\u00e9ho tlaku, a dojde k rychl\u00e9mu ochlazen\u00ed. A pr\u00e1v\u011b takov\u00e9 procesy se st\u00e1vaj\u00ed v d\u016fsledku \u00fatok\u016f z vesm\u00edru.<\/p>\n

Kennett pozd\u011bji objevil materi\u00e1l, podobn\u00fd taven\u00e9mu sklu, v tenk\u00e9 vrstv\u011b sedimentu v USA. Podle odhad\u016f i tento vznikl p\u0159ed asi 13 tis\u00edci lety p\u0159i teplot\u011b ne ni\u017e\u0161\u00ed ne\u017e 2000 stup\u0148\u016f C.<\/p>\n

Stru\u010dn\u011b \u0159e\u010deno, zd\u00e1 se, \u017ee kometa zde opravdu spadla.<\/p>\n

Ale ne na starov\u011bk\u00e9 americk\u00e9 obyvatele, ale na \u00fazem\u00ed dne\u0161n\u00edho \u00cdr\u00e1nu. Kataklysma bylo podobn\u00e9 p\u00e1du Tungusk\u00e9ho meteoritu, ale i tak bylo o n\u011bkolik \u0159\u00e1d\u016f siln\u011bj\u0161\u00ed. V\u00fdb\u011b\u017eek exploz\u00ed zas\u00e1hl a\u017e na sou\u010dasn\u00e9 \u00fazem\u00ed Spojen\u00fdch st\u00e1t\u016f a Kanady.<\/p>\n

Na Zemi se v t\u00e9 dob\u011b oteplovalo \u2013 skon\u010dila doba ledov\u00e1. A tu n\u00e1hle op\u011bt ude\u0159ilo chladn\u00e9 po\u010das\u00ed. V\u011bt\u0161ina zv\u00ed\u0159at, a s nimi i lid\u00e9 na severoamerick\u00e9m kontinentu kultury Clovis nep\u0159e\u017eili.<\/p>\n

\"\"<\/p>\n

Obr. Komet\u00e1rn\u00ed materi\u00e1l dopadl a\u017e na sousedn\u00ed kontinent. Foto: University of California<\/em><\/p>\n

Kde se v\u0161ak v Americe vzali Indi\u00e1ni?<\/strong><\/p>\n

N\u011bkte\u0159\u00ed v\u011bdci se domn\u00edvaj\u00ed, \u017ee p\u0159i\u0161li ze Sibi\u0159e.<\/p>\n

Existuj\u00ed dokonce i v\u011bdci, kte\u0159\u00ed v\u011b\u0159\u00ed, \u017ee i p\u0159edstavitel\u00e9 kultury Clovis p\u0159i\u0161li tak\u00e9 ze Sibi\u0159e, ale mnohem d\u0159\u00edve.<\/p>\n

\"\"
\nObr. Indi\u00e1ni kultury Clovis \u017eili v Severn\u00ed Americe p\u0159ed 13.000 roky, ale nep\u0159e\u017eili dopad komety<\/em><\/p>\n

Odkazy<\/em><\/strong><\/p>\n

(1) http:\/\/science.landoffree.com\/author\/Michael_I_Petaev<\/a><\/em>
\n(2) http:\/\/en.wikipedia.org\/wiki\/Clovis_culture<\/a> <\/em>
\n(3) http:\/\/www.pnas.org\/content\/104\/6\/1751.full<\/a><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

Lid\u00e9, kte\u0159\u00ed ob\u00fdvali Severn\u00ed Ameriku, byli vyhlazeni kometou, kter\u00e1 narazila do Zem\u011b p\u0159ed 13.000 lety<\/p>\n","protected":false},"author":1,"featured_media":1155,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9,17,19],"tags":[53,25,37],"class_list":["post-2329","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-historie","category-veda","category-zahady","tag-amerika","tag-katastrofy","tag-severni-amerika"],"_links":{"self":[{"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/posts\/2329","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/comments?post=2329"}],"version-history":[{"count":1,"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/posts\/2329\/revisions"}],"predecessor-version":[{"id":2333,"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/posts\/2329\/revisions\/2333"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/media\/1155"}],"wp:attachment":[{"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/media?parent=2329"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/categories?post=2329"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/tags?post=2329"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}