{"id":667,"date":"2021-12-05T09:47:12","date_gmt":"2021-12-05T07:47:12","guid":{"rendered":"https:\/\/zoobrasov.ro\/planetariu\/?p=667"},"modified":"2021-12-17T12:14:24","modified_gmt":"2021-12-17T10:14:24","slug":"in-spatiu-e-frig-de-crapa-pietrele-in-laboratoarele-de-pe-terra-ar-ingheta-si-iadul","status":"publish","type":"post","link":"https:\/\/zoobrasov.ro\/planetariu\/in-spatiu-e-frig-de-crapa-pietrele-in-laboratoarele-de-pe-terra-ar-ingheta-si-iadul\/","title":{"rendered":"\u00cen spa\u021biu, e frig de crap\u0103 pietrele, \u00een laboratoarele de pe Terra, ar \u00eenghe\u021ba \u0219i Iadul"},"content":{"rendered":"<h3>\u00cen spa\u021biu, nebuloasa Bumerang are o temperatur\u0103 de 1 k, -272,15 \u00b0C, fiind cea mai friguroas\u0103 zon\u0103 g\u0103sit\u0103 \u00een Univers, pe p\u0103m\u00e2nt, \u00een laborator, s-a atins a 38-a triliarda parte dintr-un grad Kelvin, 38 pico k (1 pico k = 1\u00d710\u203e\u00b9\u00b2\u00a0k).<\/h3>\n<p><span style=\"font-size: 14.4px;\"><span style=\"font-size: 14.4px;\">Nebuloasa Bumerang (nebuloasa Papion) este situat\u0103 \u00een constela\u021bia sudic\u0103 Centaurul, acolo unde se g\u0103se\u0219te \u0219i cel mai apropiat sistem stelar, Alpha Centauri, distan\u021ba p\u00e2n\u0103 la aceast\u0103 nebuloas\u0103 protoplanetar\u0103 fiind de 5.000 de ani lumin\u0103 (1.533 parseci). Reprezint\u0103 o faz\u0103 prin care trece steaua gigant\u0103 ro\u0219ie din centrul ei \u00een drumul spre transformarea \u00eentr-o nebuloas\u0103 planetar\u0103 (un obiect astronomic alc\u0103tuit dintr-o membran\u0103 din gaz \u0219i plasm\u0103 format\u0103 la sf\u00e2r\u0219itul vie\u021bii unor anumite stele). Praful din zona central\u0103 opre\u0219te lumina, r\u0103m\u00e2n\u00e2nd vizibili cei doi lobi situa\u021bi \u00een direc\u021bii opuse ce dau forma de clepsidr\u0103. <\/span><\/span><span style=\"font-size: 14.4px;\"><span style=\"font-size: 14.4px;\"><span style=\"font-size: 14.4px;\"><span style=\"font-size: 14.4px;\">Mi\u0219carea gazului dinspre stea spre exterior cu o vitez\u0103 de 164 km\/s, expansiunea acestui gaz, cauzeaz\u0103 temperaturile extraordinar de sc\u0103zute, de doar 1 kelvin (k*). Mai mici chiar \u0219i dec\u00e2t temperatura radia\u021biei cosmice de fond care este de 2,7 k (existen\u021ba acestei radia\u021bii este \u0219i motivul pentru care nu avem temperaturi egale cu zero absolut \u00een spa\u021biu). Mult mai mici dec\u00e2t cea mai mic\u0103 temperatur\u0103 \u00eenregistrat\u0103 \u00een Sistemul Solar, -240 \u00b0C, 33,15 kelvin, \u00eentr-un crater lunar, m\u0103sur\u0103toare f\u0103cut\u0103 de sonda LRO ce apar\u021bine NASA (un ger mai mare dec\u00e2t cel de pe Pluto). \u0218i mult, mult, mult mai mici dec\u00e2t cel mai groaznic frig de pe Terra, men\u021bionat la sta\u021biunea Vostok din Antarctica, -89,2 \u00b0C, ceea ce \u00eenseamn\u0103 183,05 kelvin.<\/span><\/span><\/span><\/span><\/p>\n<div id='gallery-1' class='gallery galleryid-667 gallery-columns-3 gallery-size-full'><figure class='gallery-item'>\n\t\t\t<div class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/zoobrasov.ro\/planetariu\/wp-content\/uploads\/2021\/11\/bumerang-nubula-3.jpg'><img loading=\"lazy\" decoding=\"async\" width=\"800\" height=\"800\" src=\"https:\/\/zoobrasov.ro\/planetariu\/wp-content\/uploads\/2021\/11\/bumerang-nubula-3.jpg\" class=\"attachment-full size-full\" alt=\"\" srcset=\"https:\/\/zoobrasov.ro\/planetariu\/wp-content\/uploads\/2021\/11\/bumerang-nubula-3.jpg 800w, https:\/\/zoobrasov.ro\/planetariu\/wp-content\/uploads\/2021\/11\/bumerang-nubula-3-300x300.jpg 300w, https:\/\/zoobrasov.ro\/planetariu\/wp-content\/uploads\/2021\/11\/bumerang-nubula-3-150x150.jpg 150w, https:\/\/zoobrasov.ro\/planetariu\/wp-content\/uploads\/2021\/11\/bumerang-nubula-3-768x768.jpg 768w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><\/a>\n\t\t\t<\/div><\/figure><figure class='gallery-item'>\n\t\t\t<div class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/zoobrasov.ro\/planetariu\/wp-content\/uploads\/2021\/11\/bumerang-nubula-2.jpg'><img loading=\"lazy\" decoding=\"async\" width=\"800\" height=\"800\" src=\"https:\/\/zoobrasov.ro\/planetariu\/wp-content\/uploads\/2021\/11\/bumerang-nubula-2.jpg\" class=\"attachment-full size-full\" alt=\"\" srcset=\"https:\/\/zoobrasov.ro\/planetariu\/wp-content\/uploads\/2021\/11\/bumerang-nubula-2.jpg 800w, https:\/\/zoobrasov.ro\/planetariu\/wp-content\/uploads\/2021\/11\/bumerang-nubula-2-300x300.jpg 300w, https:\/\/zoobrasov.ro\/planetariu\/wp-content\/uploads\/2021\/11\/bumerang-nubula-2-150x150.jpg 150w, https:\/\/zoobrasov.ro\/planetariu\/wp-content\/uploads\/2021\/11\/bumerang-nubula-2-768x768.jpg 768w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><\/a>\n\t\t\t<\/div><\/figure><figure class='gallery-item'>\n\t\t\t<div class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/zoobrasov.ro\/planetariu\/wp-content\/uploads\/2021\/11\/bumerang-nubula-1.jpg'><img loading=\"lazy\" decoding=\"async\" width=\"800\" height=\"800\" src=\"https:\/\/zoobrasov.ro\/planetariu\/wp-content\/uploads\/2021\/11\/bumerang-nubula-1.jpg\" class=\"attachment-full size-full\" alt=\"\" srcset=\"https:\/\/zoobrasov.ro\/planetariu\/wp-content\/uploads\/2021\/11\/bumerang-nubula-1.jpg 800w, https:\/\/zoobrasov.ro\/planetariu\/wp-content\/uploads\/2021\/11\/bumerang-nubula-1-300x300.jpg 300w, https:\/\/zoobrasov.ro\/planetariu\/wp-content\/uploads\/2021\/11\/bumerang-nubula-1-150x150.jpg 150w, https:\/\/zoobrasov.ro\/planetariu\/wp-content\/uploads\/2021\/11\/bumerang-nubula-1-768x768.jpg 768w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><\/a>\n\t\t\t<\/div><\/figure>\n\t\t<\/div>\n\n<p>Zero absolut, 0 k, este limita minim\u0103 pe scara de temperatur\u0103, -273,15 \u00b0C, grani\u021b\u0103 care \u00eens\u0103 nu poate fi atins\u0103, un punct de la care nu mai poate fi \u00eendep\u0103rtat\u0103 c\u0103ldur\u0103 din sistem. \u00cen accep\u021biunea clasic\u0103, zero absolut reprezint\u0103 absen\u021ba mi\u0219c\u0103rii moleculelor individuale. De fapt, mai degrab\u0103, este limita la care particulele au mi\u0219care vibra\u021bional\u0103 minim\u0103.<\/p>\n<p>* k \u2194 Lord Kelvin, numele lui William Thomson, 1824-1907, fizician irlandez care a determinat valorea corect\u0103 a temperaturii de zero absolut, dup\u0103 ce a fost \u00eennobilat de regina Victoria (Regatul Unit)<\/p>\n<p style=\"text-align: center;\"><strong>Neil deGrasse Tyson, explica\u021bii despre zero absolut!<\/strong> <em>(\u00een englez\u0103)<\/em><\/p>\n<p style=\"text-align: center;\"><iframe loading=\"lazy\" title=\"YouTube video player\" src=\"https:\/\/www.youtube.com\/embed\/aYBEcFvI8o8\" width=\"560\" height=\"315\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<p>Chiar dac\u0103 nu putem atinge 0 k, oamenii de \u0219tiin\u021b\u0103 au \u201dcobor\u00e2t\u201d foarte aproape de aceast\u0103 limit\u0103 imposibil\u0103. Cea mai joas\u0103 temperatur\u0103 atins\u0103 vreodat\u0103 a fost realizat\u0103 \u00een 2021, s-a ajuns la a 38-a triliarda parte dintr-un kelvin, 38 picokelvini (1 pico k = 1\u00d710\u203e\u00b9\u00b2 k). O echip\u0103 de cercet\u0103tori germani a \u00eenchis 100.000 de atomi de rubidiu cu ajutorul unui c\u00e2mp magnetic \u00eentr-o camer\u0103 de vacuum \u0219i i-au r\u0103cit p\u00e2n\u0103 la a 2-a miliarda parte dintr-un kelvin (au ob\u021binut un condensat Bose-Einstein*). Pentru a sc\u0103dea \u0219i mai mult temperatura, au ar\u0103tat cercet\u0103torii \u00een <span style=\"color: #0000ff;\"><a style=\"color: #0000ff;\" href=\"https:\/\/journals.aps.org\/prl\/abstract\/10.1103\/PhysRevLett.127.100401\" target=\"_blank\" rel=\"noopener\">Physical Review Letters<\/a><\/span>, au dus camera de vacuum \u00een turnul Agen\u021biei Europene Spa\u021biale din Bremen, l\u0103s\u00e2nd-o s\u0103 cad\u0103 120 de metri \u00een timp ce c\u00e2mpul magnetic era oprit \u0219i aprins foarte rapid. Condensatul Bose-Einstein (BEC) nu mai a fost astfel influen\u021bat de gravita\u021bie \u0219i mi\u0219carea molecular\u0103 a atomilor de rubidiu s-a redus aproape de tot. Rezultatul? BEC a r\u0103mas la 38 de picokelvini pentru aproximativ 2 secunde. Cercet\u0103torii au ad\u0103ugat c\u0103, teoretic, \u00een spa\u021biu, ar putea men\u021bine aceast\u0103 temperatur\u0103 pentru 17 secunde.<\/p>\n<p style=\"text-align: center;\"><strong>Cum se ajunge la temperaturi apropiate de 0 k?<\/strong> <em>(\u00een englez\u0103)<\/em><\/p>\n<p style=\"text-align: center;\"><iframe loading=\"lazy\" title=\"YouTube video player\" src=\"https:\/\/www.youtube.com\/embed\/bny5vWFi_6g\" width=\"560\" height=\"315\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<p><strong>*<\/strong> Condensatul Bose-Einstein este o stare de agregare a materiei (a cincea) ce se formeaz\u0103 atunci c\u00e2nd un gaz de bosoni la densit\u0103\u021bi mici este r\u0103cit aproape de zero absolut. Atomii ajung \u00eentr-o situa\u021bie \u00een care \u00eencep s\u0103 se comporte la unison, e ca \u0219i cum \u0219i-ar pierde individualitatea, ca \u0219i cum ar deveni invizibili, formeaz\u0103 ceea ce unii fizicieni numesc un super-atom. O stare a materiei prezis\u0103 de Albert Einstein \u0219i Satyendra Bose \u00een 1925 \u0219i produs\u0103 pentru prima dat\u0103 \u00een 1995 (un gaz din atomi de rubidiu r\u0103cit la 170 nanokelvini). C\u00e2nd se ajunge aproape de zero absolut, pe l\u00e2ng\u0103 condensatul Bose-Einstein, pot ap\u0103rea \u0219i efecte ca superfluiditatea (anumite fluide suprar\u0103cite manifest\u0103 comportamente stranii, ca \u0219i cum for\u021bele de atrac\u021bie \u0219i de frecare nu mai exist\u0103) sau superconductibilitatea (rezisten\u021ba electric\u0103 a unui material devine zero c\u00e2nd temperatura sa este mai mic\u0103 dec\u00e2t temperatura critic\u0103).<\/p>\n<p style=\"text-align: right;\"><span style=\"color: #808080;\"><em>Foto: Hubble Space Telescope\/NASA\/ESA &amp; ALMA<\/em><\/span><\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u00cen spa\u021biu, nebuloasa Bumerang are o temperatur\u0103 de 1 k, -272,15 \u00b0C, fiind cea mai friguroas\u0103 zon\u0103 g\u0103sit\u0103 \u00een Univers, pe p\u0103m\u00e2nt, \u00een laborator, s-a atins a 38-a triliarda parte dintr-un grad Kelvin, 38 pico k (1 pico k = 1\u00d710\u203e\u00b9\u00b2\u00a0k). Nebuloasa Bumerang (nebuloasa Papion) este situat\u0103 \u00een constela\u021bia sudic\u0103 Centaurul, acolo unde se g\u0103se\u0219te [&#8230;]\n","protected":false},"author":3,"featured_media":668,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[53,5],"tags":[14,19,13,22,15,18,12,20,17,16,11,21],"class_list":["post-667","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog","category-galaxii","tag-bose","tag-bumerang","tag-condensat","tag-cosmos","tag-einstein","tag-nebuloasa","tag-spatiu","tag-stele","tag-superconductibilitate","tag-superfluditate","tag-temperatura","tag-univers"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/zoobrasov.ro\/planetariu\/wp-json\/wp\/v2\/posts\/667","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/zoobrasov.ro\/planetariu\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/zoobrasov.ro\/planetariu\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/zoobrasov.ro\/planetariu\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/zoobrasov.ro\/planetariu\/wp-json\/wp\/v2\/comments?post=667"}],"version-history":[{"count":57,"href":"https:\/\/zoobrasov.ro\/planetariu\/wp-json\/wp\/v2\/posts\/667\/revisions"}],"predecessor-version":[{"id":783,"href":"https:\/\/zoobrasov.ro\/planetariu\/wp-json\/wp\/v2\/posts\/667\/revisions\/783"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/zoobrasov.ro\/planetariu\/wp-json\/wp\/v2\/media\/668"}],"wp:attachment":[{"href":"https:\/\/zoobrasov.ro\/planetariu\/wp-json\/wp\/v2\/media?parent=667"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/zoobrasov.ro\/planetariu\/wp-json\/wp\/v2\/categories?post=667"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/zoobrasov.ro\/planetariu\/wp-json\/wp\/v2\/tags?post=667"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}