\u00c7evremizdeki her \u015fey, hayvanlar, bitkiler, toprak, hava, cep telefonumuz, otomobilimiz, gezegenler, y\u0131ld\u0131zlar ve elinizde tuttu\u011funuz dergi \u201catom\u201d ad\u0131 verilen, maddenin temel yap\u0131ta\u015flar\u0131ndan olu\u015fmu\u015ftur. Peki, atomlar\u0131n k\u00f6keni nedir? Bu sorunun yan\u0131t\u0131 ger\u00e7ekten heyecan verici. \u00c7\u00fcnk\u00fc bizi ve \u00e7evremizdeki her \u015feyi olu\u015fturan elementler, B\u00fcy\u00fck Patlama\u2019dan s\u00fcpernova patlamalar\u0131na kadar bir\u00e7ok olay\u0131 ya\u015fam\u0131\u015flar.<\/p>\n
V\u00fccudumuzdaki atomlar\u0131n b\u00fcy\u00fck b\u00f6l\u00fcm\u00fc, 13,7 milyar y\u0131l \u00f6nce B\u00fcy\u00fck Patlama\u2019n\u0131n hemen ard\u0131ndan olu\u015fmu\u015f ve o g\u00fcnden bu yana de\u011fi\u015fmeden kalm\u0131\u015f durumda. Evrende en \u00e7ok bulunan element olan hidrojen, v\u00fccudumuzdaki atomlar\u0131n da \u00e7o\u011funu olu\u015fturuyor. Evrenin yakla\u015f\u0131k % 90\u2032\u0131n\u0131, v\u00fccudumuzunsa yakla\u015f\u0131k % 60\u2032\u0131n\u0131 olu\u015fturan hidrojen, ilkel evrenin olu\u015fturabilece\u011fi, sadece bir proton ve bir elektrondan olu\u015fan en basit element.<\/p>\n
Ba\u015ftan ba\u015flayal\u0131m\u2026 Bir periyodik tabloya bakt\u0131\u011f\u0131m\u0131zda hidrojenin ard\u0131ndan helyum gelir. B\u00fcy\u00fck patlama sonras\u0131nda, hidrojenden \u00e7ok daha az miktarda olmakla birlikte, iki proton ve iki n\u00f6trondan olu\u015fan helyum \u00e7ekirdekleri de olu\u015ftu. Ancak bir soy gaz olan helyum, ya\u015fam i\u00e7in gerekli di\u011fer elementlerle bile\u015fik olu\u015fturmad\u0131\u011f\u0131 i\u00e7in v\u00fccudumuzda neredeyse hi\u00e7 bulunmaz.<\/p>\n
\u00dc\u00e7\u00fcnc\u00fc s\u0131rada bulunan lityumsa eser miktarda olu\u015ftu. Evren \u00e7ok h\u0131zl\u0131 so\u011fudu\u011fu i\u00e7in lityumdan daha a\u011f\u0131r elementlerin bu s\u00fcre\u00e7te olu\u015facak f\u0131rsatlar\u0131 olamad\u0131. Bu elementlerin olu\u015fabilmesi i\u00e7in gereken bas\u0131n\u00e7 ve s\u0131cakl\u0131\u011f\u0131 ortaya \u00e7\u0131karabilecek ba\u015fka t\u00fcrl\u00fc mekanizmalar gerekiyordu.<\/p>\n
Evren birka\u00e7 milyon ya\u015f\u0131na geldi\u011finde, hidrojen ve helyumdan olu\u015fan madde, k\u00fctle\u00e7ekiminin etkisiyle s\u0131k\u0131\u015fmaya ba\u015flad\u0131. Bunlar, \u00e7e\u015fitli d\u00fczensizliklerin etkisiyle belli b\u00f6lgelerde topaklanarak ilk y\u0131ld\u0131z topluluklar\u0131n\u0131 yani g\u00f6kada k\u00fcmelerini olu\u015fturdu.<\/p>\n
\u0130lk y\u0131ld\u0131zlar\u0131n \u00e7o\u011funun k\u00fctlesi, G\u00fcne\u015f\u2019inkinden 10 ila y\u00fczlerce kat b\u00fcy\u00fckt\u00fc. Hidrojen atomu \u00e7ekirdekleri, bu y\u0131ld\u0131zlar\u0131n i\u00e7indeki y\u00fcksek bas\u0131n\u00e7 ve s\u0131cakl\u0131\u011f\u0131n etkisiyle kayna\u015farak helyuma d\u00f6n\u00fc\u015ft\u00fc. Bu ilk y\u0131ld\u0131zlar b\u00fcy\u00fck olas\u0131l\u0131kla, \u00e7ekirdeklerinde helyum yakmaya f\u0131rsat bulamadan g\u00fcn\u00fcm\u00fcz\u00fcn s\u00fcpernova patlamalar\u0131ndan \u00e7ok daha \u015fiddetli patlamalarla da\u011f\u0131ld\u0131lar.<\/p>\n
Bu patlamalarda ortaya \u00e7\u0131kan bas\u0131n\u00e7 ve s\u0131cakl\u0131k, B\u00fcy\u00fck Patlama\u2019dan sonra hi\u00e7 g\u00f6r\u00fclmedik derecede y\u00fcksekti. \u0130\u015fte hidrojen ve helyuma g\u00f6re a\u011f\u0131r elementler, ilk kez bu \u015fekilde ortaya \u00e7\u0131kmaya ba\u015flad\u0131 ve b\u00f6ylece periyodik tabloya yeni kutucuklar eklendi. Say\u0131lar\u0131 g\u00f6rece az olan bu dev y\u0131ld\u0131zlar\u0131n, evrenin kimyasal yap\u0131s\u0131nda \u00e7ok da b\u00fcy\u00fck bir de\u011fi\u015fim yaratmad\u0131\u011f\u0131 d\u00fc\u015f\u00fcn\u00fcl\u00fcyor. Yine de, daha sonra bu y\u0131ld\u0131zlar\u0131n k\u00fcllerinden olu\u015fan yeni y\u0131ld\u0131zlar\u0131n kimyasal bile\u015fimlerinde rol oynad\u0131klar\u0131 kesin.<\/p>\n
\u0130lk nesil y\u0131ld\u0131zlara g\u00f6re daha zengin bir bile\u015fime sahip olan bu ikinci nesil y\u0131ld\u0131zlar\u0131n \u00e7ekirdeklerindeki s\u0131cakl\u0131k 100.000.000\u00b0C\u2019yi a\u015fabiliyordu. Bu s\u0131cakl\u0131kta helyum \u00e7ekirdekleri kayna\u015fabildi\u011fi i\u00e7in, bir dizi zincir tepkime sonucunda evrende ilk defa karbon atomu \u00e7ekirdekleri (6 proton ve 6 n\u00f6tron) kayda de\u011fer miktarlarda olu\u015fmaya ba\u015flad\u0131.<\/p>\n
Y\u0131ld\u0131z bir kez karbon olu\u015fturmaya ba\u015flad\u0131\u011f\u0131nda, oksijenin (8 proton, 8 n\u00f6tron) olu\u015fmas\u0131 i\u00e7in \u00e7ok fazla \u0131s\u0131 ve bas\u0131nca gerek kalmaz. Karbon atomu \u00e7ekirdeklerine eklenen bir helyum atomuyla oksijen olu\u015fur. Bu a\u015famaya gelmi\u015f b\u00fcy\u00fck k\u00fctleli y\u0131ld\u0131zlar\u0131n s\u00fcpernova olarak patlamas\u0131 sonucu daha da fazla oksijen atomu \u00e7ekirde\u011fi ortaya \u00e7\u0131kar.<\/p>\n
Dikkat ettiyseniz, arada bir elementi, \u00fcstelik \u00e7ok da yayg\u0131n bir elementi atlad\u0131k. \u00c7\u00fcnk\u00fc oksijenden daha hafif bir element olan azotun (7 proton, 7 n\u00f6tron) olu\u015fumu biraz karma\u015f\u0131k. Azot da y\u0131ld\u0131zlar\u0131n \u00e7ekirdeklerinde olu\u015fur ama CNO (karbon-azot-oksijen) d\u00f6ng\u00fcs\u00fc denen bir dizi tepkimenin sonucunda\u2026<\/p>\n
Evrendeki azotun b\u00fcy\u00fck \u00e7o\u011funlu\u011funun orta k\u00fctleli y\u0131ld\u0131zlarda (1 ila 8 G\u00fcne\u015f k\u00fctlesi) olu\u015ftu\u011fu tahmin ediliyor. \u00c7\u00fcnk\u00fc bu y\u0131ld\u0131zlardaki CNO d\u00f6ng\u00fcs\u00fc daha iyi i\u015fliyor. Bu y\u0131ld\u0131zlar, evrimlerinin son a\u015famalar\u0131nda, g\u00fc\u00e7l\u00fc y\u0131ld\u0131z r\u00fczg\u00e2rlar\u0131yla azotun da i\u00e7inde bulundu\u011fu \u00e7e\u015fitli elementleri uzaya savuruyorlar.<\/p>\n
Y\u0131ld\u0131z Pe\u015finde<\/strong>:<\/span><\/p>\n G\u00f6kbilimciler, evreni olu\u015fturan elementlerin k\u00f6kenini ara\u015ft\u0131r\u0131rken birer dedektif gibi kan\u0131t pe\u015finde ko\u015fuyorlar. Ancak baz\u0131 kan\u0131tlara ula\u015fmalar\u0131 pek kolay olmayabiliyor. \u00d6rne\u011fin evreni zenginle\u015ftiren ilk nesil b\u00fcy\u00fck k\u00fctleli y\u0131ld\u0131zlar\u0131 g\u00f6zleme \u015fanslar\u0131 yok. Bu y\u0131ld\u0131zlar h\u0131zl\u0131 ya\u015fay\u0131p gen\u00e7 \u00f6ld\u00fcler. \u00c7ok k\u0131sa s\u00fcrede \u00f6m\u00fcrlerini tamamlad\u0131klar\u0131 i\u00e7in ne kadar arasalar da bulma olas\u0131l\u0131klar\u0131 yok. Buna kar\u015f\u0131n, k\u00fctleleri 0,8 G\u00fcne\u015f k\u00fctlesinden daha k\u00fc\u00e7\u00fck olan y\u0131ld\u0131zlar evrenin ya\u015f\u0131 olan 13,7 milyar y\u0131ldan uzun ya\u015fayabilirler.<\/p>\n Bu, evrendeki ilkel maddeden yap\u0131lm\u0131\u015f y\u0131ld\u0131zlar\u0131n bir yerlerde bulunabilecekleri anlam\u0131na geliyor. Bu y\u0131ld\u0131zlar\u0131 bulmak \u00f6nem ta\u015f\u0131yor. \u00c7\u00fcnk\u00fc onlar\u0131n bile\u015fiminin incelenmesiyle, ya\u015fam\u0131n temel yap\u0131ta\u015flar\u0131ndan olan karbon, azot ve oksijenin ger\u00e7ekten y\u0131ld\u0131zlarda m\u0131 \u201cpi\u015firildi\u011fini\u201d yoksa evrenin olu\u015fumuyla birlikte mi ortaya \u00e7\u0131kt\u0131\u011f\u0131n\u0131 anlayabiliriz.<\/p>\n Bu y\u0131ld\u0131zlar\u0131n, demir gibi a\u011f\u0131r elementleri pek fazla i\u00e7ermesi beklenemez. \u00c7\u00fcnk\u00fc a\u011f\u0131r elementlerin olu\u015fumu bir\u00e7ok y\u0131ld\u0131z ya\u015fam d\u00f6ng\u00fcs\u00fc gerektirir. Bu durumda aranmas\u0131 gereken, d\u00fc\u015f\u00fck k\u00fctleli ve d\u00fc\u015f\u00fck metal i\u00e7erikli y\u0131ld\u0131zlar. (G\u00f6kbilimciler, hidrojen ve helyum d\u0131\u015f\u0131ndaki t\u00fcm elementleri \u201cmetal\u201d olarak tan\u0131mlarlar).<\/p>\n G\u00f6zlemler, s\u00f6z konusu y\u0131ld\u0131zlar\u0131n ger\u00e7ekten var oldu\u011funu g\u00f6steriyor. Ne var ki say\u0131lar\u0131 pek fazla de\u011fil. \u00dcstelik \u00e7o\u011fu Samanyolu diskinin d\u0131\u015f\u0131ndaki k\u00fcresel y\u0131ld\u0131z k\u00fcmelerinin i\u00e7inde bulunuyor. Her biri y\u00fcz binlerce y\u0131ld\u0131z i\u00e7eren ve \u00e7ok uza\u011f\u0131m\u0131zda bulunan bu k\u00fcmelerdeki y\u0131ld\u0131zlar\u0131 tek tek incelemek kolay de\u011fil.<\/p>\n Buna bir \u00e7\u00f6z\u00fcm olarak ara\u015ft\u0131rmac\u0131lar binlerce y\u0131ld\u0131z\u0131n ayn\u0131 anda tayf\u0131n\u0131 \u00e7ekmek i\u00e7in bir y\u00f6ntem geli\u015ftirdiler. Y\u0131ld\u0131zlar\u0131n tayf\u0131, k\u00fc\u00e7\u00fck bir teleskopla \u00e7ekilerek bir foto\u011fraf plakas\u0131n\u0131n \u00fczerine ya da CCD alg\u0131lay\u0131c\u0131yla say\u0131sal olarak kaydediliyor ve a\u011f\u0131r elementlerin bulunmad\u0131\u011f\u0131 ya da \u00e7ok az g\u00f6r\u00fcnd\u00fc\u011f\u00fc adaylar di\u011ferlerinin aras\u0131ndan se\u00e7iliyor.<\/p>\n Bir sonraki ad\u0131m, adaylar\u0131n daha y\u00fcksek ay\u0131rt etme g\u00fcc\u00fcne sahip tayf \u00e7ekerler ve b\u00fcy\u00fck teleskoplar kullan\u0131larak incelenmesi. Bu ad\u0131m\u0131 da ba\u015far\u0131yla ge\u00e7en ve en d\u00fc\u015f\u00fck a\u011f\u0131r metal belirtisi g\u00f6steren y\u0131ld\u0131zlar, d\u00fcnyan\u0131n en b\u00fcy\u00fck teleskoplar\u0131 ve en hassas tayf \u00e7ekerleriyle inceleniyor.<\/p>\n HES (Hamburg\/ESO Ara\u015ft\u0131rmas\u0131) olarak adland\u0131r\u0131lan bir \u00e7al\u0131\u015fmada, \u015fimdiye kadar G\u00fcne\u015f\u2019in metal i\u00e7eri\u011finin % 1\u2019i kadar ya da daha az metal i\u00e7eren 2000\u2032den fazla y\u0131ld\u0131z bulundu. Bu y\u0131ld\u0131zlar\u0131n ikisi, G\u00fcne\u015f\u2019inkinin sadece milyonda biri kadar metal i\u00e7eriyor!<\/p>\n HES\u2019in yan\u0131 s\u0131ra, 2000 y\u0131l\u0131nda ba\u015flat\u0131lan ve g\u00f6ky\u00fcz\u00fcn\u00fcn yakla\u015f\u0131k d\u00f6rtte birlik bir alan\u0131n\u0131n \u00e7e\u015fitli dalga boylar\u0131nda g\u00f6r\u00fcnt\u00fclenmesi ve bu b\u00f6lgelerdeki g\u00f6kcisimlerinin tayflar\u0131n\u0131n \u00e7ekilmesini ama\u00e7layan Sloan Say\u0131sal G\u00f6ky\u00fcz\u00fc Ara\u015ft\u0131rmas\u0131 (Sloan Digital Sky Survey) kapsam\u0131nda yap\u0131lan g\u00f6zlemlerde bir seferde 640 y\u0131ld\u0131z incelenebiliyor. Bu ara\u015ft\u0131rma kapsam\u0131nda bulunan metal fakiri y\u0131ld\u0131z say\u0131s\u0131, \u00f6nceki ara\u015ft\u0131rmalarda bulunanlar\u0131n \u00fc\u00e7 kat\u0131na \u00e7\u0131km\u0131\u015f durumda.<\/p>\n Ara\u015ft\u0131rmalar\u0131n sonu\u00e7lar\u0131 g\u00f6steriyor ki, G\u00fcne\u015f\u2019in 100\u2032de birinden az metalli\u011fe sahip y\u0131ld\u0131zlar\u0131n % 20\u2019si atmosferindeki demire g\u00f6re, yine atmosferinde \u00e7ok y\u00fcksek karbon oran\u0131na sahip. Bu oran G\u00fcne\u015f\u2019in karbon\/demir oran\u0131n\u0131n 10.000 kat\u0131na kadar \u00e7\u0131k\u0131yor. Bunun yan\u0131 s\u0131ra, bu y\u0131ld\u0131zlarda azot ve oksijenin demire oranlar\u0131 da \u00e7ok daha y\u00fcksek. Bu g\u00f6zlemler, karbon, azot ve oksijenin ilkel evrende bolca \u00fcretildi\u011fini g\u00f6steriyor.<\/p>\n Element F\u0131r\u0131nlar\u0131<\/strong>:<\/span><\/p>\n V\u00fccudumuzu olu\u015fturan atomlar\u0131n say\u0131ca % 62\u2019si hidrojen, % 24\u2032\u00fc oksijen, % 12\u2019si karbon ve % 1\u2019i azottan olu\u015fuyor. Bu oranlar\u0131 toplad\u0131\u011f\u0131m\u0131zda, v\u00fccudumuzun % 99\u2032unu olu\u015fturan atomlar\u0131n \u00e7o\u011funun B\u00fcy\u00fck Patlama\u2019n\u0131n k\u0131sa bir s\u00fcre sonras\u0131nda, geri kalan\u0131n\u0131nsa ilk y\u0131ld\u0131zlarda olu\u015ftu\u011funu s\u00f6yleyebiliriz.<\/p>\n Peki, geriye kalan % 1\u2019lik oran nelerden olu\u015fuyor? Oran k\u00fc\u00e7\u00fck g\u00f6r\u00fcnse de bunlar vazge\u00e7ebilece\u011fimiz t\u00fcrden elementler de\u011fil. Bunlar\u0131n \u00e7o\u011fu, ya\u015fam i\u00e7in \u201colmazsa olmaz\u201d yap\u0131ta\u015flar\u0131. Asl\u0131nda say\u0131ca % 1\u2019i olu\u015ftursalar da, k\u00fctleleri hidrojene g\u00f6re \u00e7ok daha b\u00fcy\u00fck oldu\u011fu i\u00e7in a\u011f\u0131rl\u0131\u011f\u0131m\u0131z\u0131n % 1\u2019den daha fazlas\u0131n\u0131 olu\u015fturuyorlar. Bir multivitamin kutusunun \u00fczerinde \u00e7o\u011funun ad\u0131n\u0131 s\u00f6ylemekte bile zorland\u0131\u011f\u0131m\u0131z bir\u00e7ok element s\u0131raland\u0131\u011f\u0131n\u0131 g\u00f6r\u00fcr\u00fcz.<\/p>\n Bu elementlerin baz\u0131s\u0131 evrende \u00e7ok az miktarlarda bulunur. G\u00fcnl\u00fck ya\u015famda da g\u0131dalardan fark\u0131nda olmad\u0131\u011f\u0131m\u0131z bir \u015fekilde ald\u0131klar\u0131m\u0131z d\u0131\u015f\u0131nda pek kar\u015f\u0131m\u0131za \u00e7\u0131kmazlar. \u00d6rne\u011fin molibden G\u00fcne\u015f Sistemi\u2019nin yaln\u0131zca 10 milyarda birini olu\u015fturur. Ancak \u00e7ok az miktarlarda da olsa, v\u00fccudumuzun \u00e7e\u015fitli i\u015flevlerini yerine getirebilmesi i\u00e7in gereksinim duydu\u011fumuz bir elementtir. Bu element, G\u00fcne\u015f\u2019ten daha b\u00fcy\u00fck k\u00fctleli y\u0131ld\u0131zlar\u0131n ya\u015fam\u0131n\u0131n son a\u015famalar\u0131nda, yani y\u0131ld\u0131z \u00f6l\u00fcrken olu\u015fur.<\/p>\n \u00c7ekirde\u011finde hidrojen yakan bir y\u0131ld\u0131z, ya\u015fam\u0131n\u0131n ortalar\u0131nda kararl\u0131 bir duruma gelir. Y\u0131ld\u0131z\u0131n merkezindeki tepkimeler, d\u0131\u015fa do\u011fru bir bas\u0131n\u00e7 yarat\u0131r. K\u00fctle\u00e7ekimiyse buna z\u0131t y\u00f6nl\u00fc bir kuvvet uygular. Kuvvetler dengelenir ve y\u0131ld\u0131z \u00e7\u00f6kmekten oldu\u011fu gibi geni\u015fleyip da\u011f\u0131lmaktan da kurtulur.<\/p>\n 1 ila 8 G\u00fcne\u015f k\u00fctlesine sahip bir y\u0131ld\u0131z, \u00e7ekirde\u011findeki hidrojeni t\u00fcketti\u011finde, k\u00fctle\u00e7ekimi bask\u0131n hale gelir ve y\u0131ld\u0131z \u00e7\u00f6kmeye ba\u015flar. Ta ki y\u0131ld\u0131z\u0131n \u00e7ekirde\u011findeki s\u0131cakl\u0131k helyum \u00e7ekirdeklerini kayna\u015ft\u0131rmaya yetecek kadar y\u00fckselene dek. Bu durum y\u0131ld\u0131z\u0131n geni\u015flemesine ve y\u00fczeyinin so\u011fumas\u0131na neden olur. Ard\u0131ndan d\u00f6ng\u00fc tekrarlar.<\/p>\n Bu zonklamalar s\u0131ras\u0131nda 6 proton ve 7 n\u00f6trondan olu\u015fan karbon-13 \u00e7ekirdekleri, 2 proton ve 2 n\u00f6trondan olu\u015fan helyum \u00e7ekirdekleriyle kayna\u015f\u0131r. Bu \u00e7ekirdek tepkimeleri, v\u00fccudumuzdaki atomlar\u0131n d\u00f6rtte birini olu\u015fturan oksijeni (8 proton, 8 n\u00f6tron) olu\u015fturur. Her bir tepkimenin sonucunda da bir n\u00f6tron a\u00e7\u0131kta kal\u0131r.<\/p>\n \u00c7ekirdeklerindeki bas\u0131n\u00e7 ve s\u0131cakl\u0131k daha y\u00fcksek olan daha b\u00fcy\u00fck k\u00fctleli y\u0131ld\u0131zlarda, neon-22 ve helyum-4 kayna\u015fmas\u0131 sonucu olu\u015fan magnezyum-25 ile birlikte yine bir n\u00f6tron a\u00e7\u0131\u011fa \u00e7\u0131kar. Magnezyum, v\u00fccudumuzda eser miktarda bulunsa da protein sentezi, kaslar\u0131n kas\u0131lmas\u0131 ve sinirler aras\u0131 ileti\u015fimin ger\u00e7ekle\u015febilmesi i\u00e7in gerekli bir elementtir.<\/p>\n A\u00e7\u0131\u011fa \u00e7\u0131kan \u00e7ok miktarda n\u00f6tronsa, y\u0131ld\u0131z\u0131n \u00e7ekirde\u011finde kaynayan kazan\u0131n i\u00e7inde kayna\u015facak ba\u015fka \u00e7ekirdekler arar. \u00d6rne\u011fin, n\u00f6tronlar\u0131n bir demir \u00e7ekirde\u011fiyle kayna\u015fmas\u0131yla demirin \u00e7e\u015fitli izotoplar\u0131 olu\u015fur. Normalde demirin proton ve n\u00f6tron say\u0131lar\u0131 e\u015fitken (26 proton, 26 n\u00f6tron) \u00e7ekirde\u011fe kayna\u015fan n\u00f6tronlar bu e\u015fitli\u011fi bozar. Kayna\u015fan n\u00f6tronlara kar\u015f\u0131n atom \u00e7ekirde\u011fi kararl\u0131 yap\u0131s\u0131n\u0131 koruyabilir.<\/p>\n Ancak, \u00e7ok fazla say\u0131daki n\u00f6tron, \u00e7ekirde\u011fi karars\u0131z hale getirir ve n\u00f6tronlardan biri protona d\u00f6n\u00fc\u015f\u00fcverir. Bu s\u0131rada bir elektron a\u00e7\u0131\u011fa \u00e7\u0131kar ve \u00e7ekirdek b\u00f6ylece beta \u0131\u015f\u0131n\u0131m\u0131 yapm\u0131\u015f olur (elektronlar ayn\u0131 zamanda beta par\u00e7ac\u0131\u011f\u0131 olarak da bilinir). Proton say\u0131s\u0131 de\u011fi\u015fen element art\u0131k ba\u015fka bir elemente d\u00f6n\u00fc\u015fm\u00fc\u015ft\u00fcr. Periyodik tabloda bir kutucuk daha\u2026<\/p>\n Orta k\u00fctleli bir y\u0131ld\u0131z\u0131n zonklamalar\u0131 s\u0131ras\u0131nda \u00e7ekirde\u011finin santimetre-k\u00fcp\u00fcnde 100 milyon kadar n\u00f6tron v\u0131z\u0131r v\u0131z\u0131r u\u00e7u\u015fur. Bu, g\u00f6kbilimsel bak\u0131mdan o kadar da y\u00fcksek bir yo\u011funluk de\u011fildir. B\u00f6ylece, yeni olu\u015fan izotoplar yeni bir n\u00f6tronla \u00e7arp\u0131\u015fmadan \u00f6nce, kendilerini n\u00f6tron-proton d\u00f6n\u00fc\u015f\u00fcm\u00fcyle dengeleyecek zaman\u0131 bulurlar. Bu yolla giderek daha a\u011f\u0131r \u00e7ekirdeklerin olu\u015fmas\u0131na \u201cyava\u015f s\u00fcre\u00e7\u201d deniyor.<\/p>\n Olay\u0131n bu \u015fekilde adland\u0131r\u0131lmas\u0131n\u0131n nedeni, \u00e7ekirde\u011fin n\u00f6tronlarla kayna\u015fma h\u0131z\u0131n\u0131n beta bozunumu h\u0131z\u0131na g\u00f6re yava\u015f kalmas\u0131. Bu mekanizmayla olu\u015fan elementler de \u201cyava\u015f s\u00fcre\u00e7 elementleri\u201d olarak adland\u0131r\u0131l\u0131yor. Bu s\u00fcreci hararetle ya\u015fayan, yani \u00e7ekirde\u011finde yo\u011fun bir \u015fekilde \u00e7ekirdek-n\u00f6tron kayna\u015fmas\u0131 ve beta bozunumu ger\u00e7ekle\u015ftiren y\u0131ld\u0131zlar, \u00e7ekirdeklerindeki demirin bir b\u00f6l\u00fcm\u00fcn\u00fc v\u00fccudumuzun i\u015fleyi\u015fi i\u00e7in gerekli olan molibden elementine d\u00f6n\u00fc\u015ft\u00fcr\u00fcr. \u0130\u015fte, ya\u015fam\u0131 olu\u015fturan elementlerin nas\u0131l ortaya \u00e7\u0131kt\u0131\u011f\u0131n\u0131, y\u0131ld\u0131zlar\u0131n i\u00e7inde neler olup bitti\u011fini anlayarak bu \u015fekilde bulabiliyoruz.<\/p>\n Peki, nas\u0131l oluyor da \u00e7ap\u0131 milyonlarca kilometreyi bulan bu dev g\u00f6kcisimlerinin \u00e7ekirde\u011findeki maddeler, g\u00f6kadam\u0131z\u0131n her yan\u0131na yay\u0131lm\u0131\u015f olarak bulunuyor? Y\u0131ld\u0131zlar\u0131 kat\u0131 cisimler gibi d\u00fc\u015f\u00fcnmemek gerek. Her ne kadar b\u00fcy\u00fck k\u00fctleli bir y\u0131ld\u0131z\u0131n \u00e7ekirde\u011fi demirden olu\u015fsa da buradaki s\u0131cakl\u0131k o kadar y\u00fcksektir ki, buras\u0131 kaynayan bir kazan\u0131n i\u00e7i gibi s\u00fcrekli hareket halindedir.<\/p>\n Y\u0131ld\u0131z\u0131n i\u00e7indeki \u0131s\u0131, \u0131\u015f\u0131n\u0131m\u0131n yan\u0131 s\u0131ra \u00e7alkant\u0131larla d\u0131\u015f katmanlara iletilir. Yani, y\u0131ld\u0131z olu\u015fturan madde s\u00fcrekli hareket halindedir. B\u00f6ylece, \u00e7ekirdekte ve \u00e7evresinde \u201cpi\u015firilen\u201d yeni elementler y\u0131ld\u0131z\u0131n \u00fcst katmanlar\u0131na kadar ula\u015fabilir. Y\u0131ld\u0131z \u00f6mr\u00fcn\u00fc tamamlad\u0131\u011f\u0131nda \u00fcst katmanlar\u0131n\u0131 uzaya savurur. \u0130\u015fte bu madde bir gezegenimsi bulutsu olarak geni\u015fler ve y\u0131ld\u0131zdan uzaklara ta\u015f\u0131n\u0131r.<\/p>\n V\u00fccudumuzdaki molibdenin \u00e7o\u011fu, ayr\u0131ca stronsiyum, itriyum, baryum, lantan, seryum ve kur\u015funun tamam\u0131na yak\u0131n\u0131, y\u0131ld\u0131z\u0131m\u0131z G\u00fcne\u015f\u2019in atalar\u0131n\u0131n i\u00e7inde, yava\u015f s\u00fcre\u00e7ler s\u0131ras\u0131nda olu\u015fmu\u015f. G\u00fcne\u015f Sistemimiz de bu y\u0131ld\u0131zlar\u0131n k\u00fcllerinden var olmu\u015f ve bu elementler t\u00fcm canl\u0131lara ya\u015fam vermi\u015f..<\/p>\n Patlayan F\u0131r\u0131nlar:<\/strong><\/span><\/p>\n Bir y\u0131ld\u0131z\u0131n i\u00e7inde olu\u015fan elementler, v\u00fccudumuzun neredeyse t\u00fcm gereksinimlerini kar\u015f\u0131lar. Ancak, \u00f6rne\u011fin iyot olmadan sa\u011fl\u0131kl\u0131 bir ya\u015fam s\u00fcremeyiz. Bu elementse y\u0131ld\u0131zlar\u0131n i\u00e7inde \u00fcretilemiyor. Bunun i\u00e7in \u00e7ok daha fazlas\u0131, ne kadar b\u00fcy\u00fck olursa olsun bir y\u0131ld\u0131z\u0131n i\u00e7inde olu\u015fmas\u0131 m\u00fcmk\u00fcn olmayan ko\u015fullar gerekli.<\/p>\n \u0130\u015fte bu ko\u015fullar yaln\u0131zca s\u00fcpernova patlamas\u0131 denen \u00e7ok g\u00fc\u00e7l\u00fc patlamalar s\u0131ras\u0131nda ortaya \u00e7\u0131kabiliyor. Y\u0131ld\u0131zlar s\u00fcpernova olarak patlad\u0131klar\u0131nda, o kadar yo\u011fun bir \u015fekilde n\u00f6tron bombard\u0131man\u0131na u\u011frarlar ki beta bozunumuyla kendilerini dengeleyecek f\u0131rsat\u0131 bulamazlar.<\/p>\n \u00c7ok b\u00fcy\u00fck k\u00fctleli y\u0131ld\u0131zlar\u0131n patlamas\u0131yla olu\u015fan tip II s\u00fcpernovalarda, atom \u00e7ekirdekleri n\u00f6tronlar taraf\u0131ndan \u00e7ok yo\u011fun bir \u015fekilde bombard\u0131mana tutulur. Bu s\u0131rada, n\u00f6tron yo\u011funlu\u011fu santimetrek\u00fcp ba\u015f\u0131na y\u00fcz milyar kere trilyona \u00e7\u0131kar. (Hat\u0131rlarsan\u0131z, yava\u015f s\u00fcre\u00e7 s\u0131ras\u0131nda n\u00f6tron yo\u011funlu\u011fu santimetrek\u00fcp ba\u015f\u0131na y\u00fcz milyard\u0131.)<\/p>\n \u0130\u015fte atom \u00e7ekirdeklerinin beta bozunumuyla dengelenemedikleri bu s\u00fcrece \u201ch\u0131zl\u0131 s\u00fcre\u00e7\u201d deniyor. \u0130\u015fte bu s\u00fcre\u00e7 s\u0131ras\u0131nda ortaya \u00e7\u0131kan enerji, s\u00fcpernovan\u0131n parlakl\u0131\u011f\u0131n\u0131 korumas\u0131na, hatta bir s\u00fcre daha art\u0131rmas\u0131na neden olabilir. Ancak olay biraz yat\u0131\u015ft\u0131ktan sonra, karars\u0131z durumdaki atom \u00e7ekirdekleri bozunarak kararl\u0131 izotoplara d\u00f6n\u00fc\u015febilirler<\/p>\n Ortal\u0131k sakinle\u015fti\u011finde ortaya g\u00fcm\u00fc\u015f, alt\u0131n ve platin gibi fazlaca de\u011fer verdi\u011fimiz elementlerin yan\u0131 s\u0131ra, yukar\u0131da s\u00f6z\u00fcn\u00fc etti\u011fimiz iyot da ortaya \u00e7\u0131kar. Bunlar\u0131n yan\u0131 s\u0131ra, h\u0131zl\u0131 s\u00fcre\u00e7 sonunda, biyolojik a\u00e7\u0131dan \u00f6nemli bir\u00e7ok hafif element de olu\u015fmu\u015f olur. Kalsiyum, magnezyum, silisyum, k\u00fck\u00fcrt ve titanyum bunlardan baz\u0131lar\u0131.<\/p>\n Baz\u0131 elementlerinse hangi s\u00fcre\u00e7lerde ortaya \u00e7\u0131kt\u0131\u011f\u0131 tam bilinmiyor. \u00d6rne\u011fin, her iki s\u00fcre\u00e7te de selenyum olu\u015fabiliyor. Sa\u011fl\u0131kl\u0131 bir ba\u011f\u0131\u015f\u0131kl\u0131k sistemi i\u00e7in gerekli olan selenyumun yakla\u015f\u0131k \u00fc\u00e7te ikisinin h\u0131zl\u0131 s\u00fcre\u00e7lerde, geriye kalan\u0131n\u0131nsa yava\u015f s\u00fcre\u00e7lerde olu\u015ftu\u011fu d\u00fc\u015f\u00fcn\u00fcl\u00fcyor.<\/p>\n Canl\u0131lar i\u00e7in vazge\u00e7ilmez bir element olan demir, tip II s\u00fcpernovalar s\u0131ras\u0131nda uzaya belli \u00f6l\u00e7\u00fcde sa\u00e7\u0131l\u0131yor. Ancak, y\u0131ld\u0131z\u0131n \u00e7ekirde\u011findeki demirin \u00e7o\u011fu, y\u0131ld\u0131z\u0131n k\u00fctlesine ba\u011fl\u0131 olarak karadeli\u011fe, n\u00f6tron y\u0131ld\u0131z\u0131na ya da beyaz c\u00fcceye d\u00f6n\u00fc\u015f\u00fcyor. G\u00f6kbilimciler, G\u00fcne\u015f benzeri y\u0131ld\u0131zlar\u0131n \u00fcr\u00fcn\u00fc olan beyaz c\u00fccelerin, G\u00fcne\u015f Sistemi\u2019ndeki demirin ana kayna\u011f\u0131 oldu\u011funu tahmin ediyorlar. Bir\u00e7ok y\u0131ld\u0131z, evrende tek ba\u015f\u0131na bulunmaz.<\/p>\n Bunun yerine, ikili ya da \u00e7oklu sistemler olu\u015ftururlar. Bunlardan baz\u0131lar\u0131 birbirlerine o kadar yak\u0131n dolan\u0131r ki, birinin di\u011feri \u00fczerinde \u00e7e\u015fitli etkileri olabilir. Dev bir y\u0131ld\u0131z ve bir beyaz c\u00fcceden olu\u015fan ikili sistemde dev y\u0131ld\u0131zdan beyaz c\u00fcceye madde ak\u0131m\u0131 olabilir. Bunun \u00e7e\u015fitli \u00f6rnekleri g\u00f6zleniyor. E\u011fer bir beyaz c\u00fcce a\u015f\u0131r\u0131 miktarda k\u00fctle biriktirirse patlayabilir. \u0130\u015fte bu patlamalar, demiri d\u00f6rt bir yan\u0131na sa\u00e7ar.<\/p>\n G\u00fcne\u015f benzeri y\u0131ld\u0131zlar\u0131n \u00fcr\u00fcn\u00fc beyaz c\u00fccelerin, G\u00fcne\u015f sistemindeki demirin ana kayna\u011f\u0131 oldu\u011fu tahmin ediliyor. G\u00f6kbilimciler \u00e7ok uzaklarda, eri\u015femeyece\u011fimiz kadar uzakta bulunan g\u00f6kcisimleri \u00fczerinde \u00e7al\u0131\u015f\u0131rken, asl\u0131nda k\u00f6kenimizle ilgili merak etti\u011fimiz, nas\u0131l ve neden olu\u015ftu\u011fumuz sorular\u0131n\u0131n yan\u0131t\u0131n\u0131 da bulmaya \u00e7al\u0131\u015f\u0131yorlar. \u015eimdilik sahip oldu\u011fumuz bilgiler \u0131\u015f\u0131\u011f\u0131nda, bizi olu\u015fturan elementlerin bir b\u00f6l\u00fcm\u00fcn\u00fcn B\u00fcy\u00fck Patlama s\u0131ras\u0131nda, bir b\u00f6l\u00fcm\u00fcn\u00fcn y\u0131ld\u0131zlar\u0131n i\u00e7inde, kalan\u0131n\u0131n da s\u00fcpernova patlamalar\u0131nda olu\u015ftu\u011funu rahatl\u0131kla s\u00f6yleyebiliyoruz. Sonu\u00e7ta hepimiz y\u0131ld\u0131z tozundan yap\u0131lm\u0131\u015f\u0131z\u2026<\/p>\n Evren ve \u0130nsan<\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":" \u00c7evremizdeki her \u015fey, hayvanlar, bitkiler, toprak, hava, cep telefonumuz, otomobilimiz, gezegenler, y\u0131ld\u0131zlar ve elinizde tuttu\u011funuz dergi \u201catom\u201d ad\u0131 verilen, maddenin temel yap\u0131ta\u015flar\u0131ndan olu\u015fmu\u015ftur. Peki, atomlar\u0131n k\u00f6keni nedir? Bu sorunun yan\u0131t\u0131 ger\u00e7ekten heyecan verici. \u00c7\u00fcnk\u00fc bizi ve \u00e7evremizdeki her \u015feyi olu\u015fturan elementler, B\u00fcy\u00fck Patlama\u2019dan s\u00fcpernova patlamalar\u0131na kadar bir\u00e7ok olay\u0131 ya\u015fam\u0131\u015flar. V\u00fccudumuzdaki atomlar\u0131n b\u00fcy\u00fck b\u00f6l\u00fcm\u00fc, 13,7 milyar …<\/p>\n","protected":false},"author":1,"featured_media":1186,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[22],"tags":[],"class_list":["post-1185","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-astronomi"],"_links":{"self":[{"href":"http:\/\/kosmosmacerasi.com\/v1\/wp-json\/wp\/v2\/posts\/1185","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/kosmosmacerasi.com\/v1\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/kosmosmacerasi.com\/v1\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/kosmosmacerasi.com\/v1\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/kosmosmacerasi.com\/v1\/wp-json\/wp\/v2\/comments?post=1185"}],"version-history":[{"count":1,"href":"http:\/\/kosmosmacerasi.com\/v1\/wp-json\/wp\/v2\/posts\/1185\/revisions"}],"predecessor-version":[{"id":1187,"href":"http:\/\/kosmosmacerasi.com\/v1\/wp-json\/wp\/v2\/posts\/1185\/revisions\/1187"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/kosmosmacerasi.com\/v1\/wp-json\/wp\/v2\/media\/1186"}],"wp:attachment":[{"href":"http:\/\/kosmosmacerasi.com\/v1\/wp-json\/wp\/v2\/media?parent=1185"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/kosmosmacerasi.com\/v1\/wp-json\/wp\/v2\/categories?post=1185"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/kosmosmacerasi.com\/v1\/wp-json\/wp\/v2\/tags?post=1185"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}