{"id":37763,"date":"2019-10-30T03:53:07","date_gmt":"2019-10-30T00:53:07","guid":{"rendered":"https:\/\/bilimvegelecek.com.tr\/?p=37763"},"modified":"2019-10-28T14:02:47","modified_gmt":"2019-10-28T11:02:47","slug":"evren-ne-kadar-buyuktur","status":"publish","type":"post","link":"https:\/\/bilimvegelecek.com.tr\/index.php\/2019\/10\/30\/evren-ne-kadar-buyuktur","title":{"rendered":"Evren ne kadar b\u00fcy\u00fckt\u00fcr?"},"content":{"rendered":"

\u00c7ocuklu\u011fumuzda g\u00f6ky\u00fcz\u00fcne bakt\u0131\u011f\u0131m\u0131zda akl\u0131ma ilk gelen sorulardan biridir evrenin b\u00fcy\u00fckl\u00fc\u011f\u00fc. Akl\u0131m\u0131z ve yorumlar\u0131m\u0131z ise ya\u015fad\u0131\u011f\u0131m\u0131z d\u00fcnyan\u0131n nesneleri ile yan\u0131tlar arama yolundad\u0131r. Neredeyse t\u00fcm insanl\u0131\u011f\u0131n merak etti\u011fi bir soru olarak Evren ne kadar b\u00fcy\u00fckt\u00fcr?<\/p>\n

Soruya \u00c7a\u011flar Sunay\u2019\u0131n Bilim ve Gelecek Kitapl\u0131\u011f\u0131 i\u00e7in haz\u0131rlam\u0131\u015f oldu\u011fu “50 Soruda Evren” kitab\u0131ndan yan\u0131tlar arad\u0131k.<\/p>\n

1838\u2019de Alman g\u00f6kbilimci Friedrich Bessel yak\u0131n y\u0131ld\u0131zlardan baz\u0131lar\u0131n\u0131n uzakl\u0131\u011f\u0131n\u0131 ilk kez do\u011fru \u00f6l\u00e7ene kadar Evren\u2019in ne kadar b\u00fcy\u00fck oldu\u011funa ili\u015fkin hi\u00e7 kimsenin bir fikri yoktu. Bessel, 61Cygni adl\u0131 y\u0131ld\u0131z\u0131n 0,31 saniyelik bir paralaks\u0131 oldu\u011funu (art\u0131k 0,287 saniye oldu\u011funu biliyoruz) \u00f6l\u00e7t\u00fc ve yapt\u0131\u011f\u0131 hesaba g\u00f6re 61Cygni\u2019nin 93 trilyon kilometreden, yani 10 \u0131\u015f\u0131k y\u0131l\u0131ndan biraz daha uzak oldu\u011funu buldu. B\u00f6ylece geceleri g\u00f6ky\u00fcz\u00fcnde nokta kadar g\u00f6rd\u00fc\u011f\u00fcm\u00fcz y\u0131ld\u0131zlar\u0131n bize ve birbirlerine olan uzakl\u0131\u011f\u0131 hakk\u0131nda ilk kez bir fikrimiz oldu. 20. y\u00fczy\u0131l\u0131n ba\u015flar\u0131na kadar da Evren\u2019in yaln\u0131zca Samanyolu\u2019ndaki milyarlarca y\u0131ld\u0131zdan olu\u015ftu\u011fu ve durgun oldu\u011fu d\u00fc\u015f\u00fcn\u00fcld\u00fc.<\/p>\n

Hubble 1923\u2019te Andromeda Bulutsusu\u2019nun Samanyolu\u2019nun i\u00e7inde yer alamayacak kadar uzakta oldu\u011funu ke\u015ffedince, bir gecede Evren\u2019imizin boyutlar\u0131 trilyonlarca kat b\u00fcy\u00fcy\u00fcverdi. Andromeda da t\u0131pk\u0131 Samanyolu gibi ba\u015fl\u0131 ba\u015f\u0131na bir g\u00f6kadayd\u0131 ve milyarlarca y\u0131ld\u0131zdan olu\u015fuyordu. Asl\u0131nda sarmal bulutsu san\u0131lan yap\u0131lar\u0131n hepsi uzak birer g\u00f6kadayd\u0131 ve Evren\u2019de onlardan milyarlarca vard\u0131.<\/p>\n

21. y\u00fczy\u0131la geldik ve aradan yakla\u015f\u0131k y\u00fczy\u0131l ge\u00e7mesine kar\u015f\u0131n, g\u00f6kbilimciler Evren\u2019in tam olarak ne kadar b\u00fcy\u00fck oldu\u011funu h\u00e2l\u00e2 bilemiyor; belki de hi\u00e7 bilemeyecekler. Sonsuz b\u00fcy\u00fck olma olas\u0131l\u0131\u011f\u0131 var ama, bilim insanlar\u0131 sonlu bir b\u00fcy\u00fckl\u00fc\u011f\u00fc oldu\u011funu d\u00fc\u015f\u00fcnme e\u011filimindeler.<\/p>\n

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William Herschel\u2019in 1785\u2019te yapt\u0131\u011f\u0131 bu \u201cSamanyolu haritas\u0131\u201d. \u00c7ok uzun bir s\u00fcre Evren\u2019in yaln\u0131zca Samanyolu\u2019ndan ibaret oldu\u011fu d\u00fc\u015f\u00fcn\u00fclm\u00fc\u015ft\u00fcr.<\/figcaption><\/figure>\n

Her ne kadar Evren\u2019in bir s\u0131n\u0131r\u0131 yoksa ve sonsuz b\u00fcy\u00fckl\u00fckte olabilirse de, bizim hakk\u0131nda bilgi sahibi olabildi\u011fimiz (gelen \u0131\u015f\u0131klar sayesinde g\u00f6zleyebildi\u011fimiz) s\u0131n\u0131rl\u0131 bir Evren b\u00f6lgesi vard\u0131r. Buna \u201cg\u00f6zlemlenebilir Evren\u201d denir. G\u00f6zlemlenebilir Evren, merkezinde D\u00fcnya\u2019n\u0131n bulundu\u011fu dev bir balon gibi d\u00fc\u015f\u00fcn\u00fclebilir. Bunun i\u00e7inde \u0131\u015f\u0131klar\u0131n\u0131n bize ula\u015fmas\u0131 13,75 milyar y\u0131ldan daha k\u0131sa s\u00fcren b\u00fct\u00fcn g\u00f6kadalar yer al\u0131r. Bu da Evren\u2019in var oldu\u011fu \u2013ilk \u0131\u015f\u0131klar\u0131n yola \u00e7\u0131kt\u0131\u011f\u0131- s\u00fcredir.<\/p>\n

Evren\u2019in s\u00fcrekli geni\u015fliyor olmas\u0131, \u201cuzakl\u0131k\u201d olgusunu, \u00f6zellikle uzak nesneler i\u00e7in olduk\u00e7a karma\u015f\u0131kla\u015ft\u0131r\u0131r. G\u00f6kbilimciler b\u00fcy\u00fck uzakl\u0131klar\u0131 anlatmak i\u00e7in genellikle \u0131\u015f\u0131\u011f\u0131n yolculuk etti\u011fi s\u00fcreyi kullan\u0131rlar. Bu da \u0131\u015f\u0131\u011f\u0131n, kayna\u011f\u0131n\u0131 terk etti\u011fi anla bize ula\u015ft\u0131\u011f\u0131 an aras\u0131nda ge\u00e7en zamand\u0131r. Ama \u0131\u015f\u0131\u011f\u0131n yolculu\u011fu s\u0131ras\u0131nda Evren geni\u015flemi\u015ftir; yol almakta olan \u0131\u015f\u0131\u011f\u0131n hem \u00f6n\u00fcndeki hem de arkas\u0131ndaki Evren. Bir ba\u015fka deyi\u015fle o bize do\u011fru gelirken Evren\u2019in geni\u015flemesi nedeniyle aram\u0131zdaki uzakl\u0131k bir miktar artm\u0131\u015ft\u0131r. O nedenle \u0131\u015f\u0131k, nesneyi terk edip bize do\u011fru yola \u00e7\u0131kt\u0131\u011f\u0131 anda, bizimle \u0131\u015f\u0131k kayna\u011f\u0131n\u0131n aras\u0131ndaki uzakl\u0131k, \u0131\u015f\u0131k g\u00f6z\u00fcm\u00fcze geldi\u011fi andaki uzakl\u0131ktan daha k\u0131sad\u0131r\u00a0 ge\u00e7mi\u015fte. Bununla birlikte \u0131\u015f\u0131k kayna\u011f\u0131n\u0131n \u015fu anki konumu da g\u00f6nderdi\u011fi \u0131\u015f\u0131\u011f\u0131n, \u0131\u015f\u0131k h\u0131z\u0131yla ald\u0131\u011f\u0131ndan daha da uzakt\u0131r. \u00c7\u00fcnk\u00fc o da g\u00f6nderdi\u011fi \u0131\u015f\u0131k bize do\u011fru ilerlerken oldu\u011fu yerde sabit kalmam\u0131\u015f, Evren geni\u015fledi\u011fi i\u00e7in ters y\u00f6nde ilerlemi\u015ftir.<\/p>\n

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On bir milyar y\u0131l \u00f6nce X g\u00f6kadas\u0131ndan \u00e7\u0131kan bir \u0131\u015f\u0131k fotonu Samanyolu\u2019na do\u011fru ilerlemeye ba\u015flam\u0131\u015ft\u0131r. O d\u00f6nemde iki g\u00f6kada aras\u0131ndaki uzakl\u0131k yaln\u0131zca 4 milyar \u0131\u015f\u0131k y\u0131l\u0131d\u0131r.<\/figcaption><\/figure>\n
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Alt\u0131 milyar y\u0131l sonra foton h\u00e2l\u00e2 Samanyolu\u2019na varamam\u0131\u015ft\u0131r; \u00e7\u00fcnk\u00fc o yol al\u0131rken Evren geni\u015flemi\u015f ve ula\u015fmaya \u00e7al\u0131\u015ft\u0131\u011f\u0131 Samanyolu ondan uzakla\u015fm\u0131\u015ft\u0131r.<\/figcaption><\/figure>\n
\"\"
Foton Samanyolu\u2019na ula\u015fm\u0131\u015f ve D\u00fcnya\u2019daki bir g\u00f6zlemci de X g\u00f6kadas\u0131n\u0131 11 milyar \u0131\u015f\u0131k y\u0131l\u0131 \u00f6tede g\u00f6rm\u00fc\u015ft\u00fcr. Ancak foton Samanyolu\u2019na do\u011fru ilerlerken Evren\u2019in geni\u015flemesi nedeniyle X g\u00f6kadas\u0131 Samanyolu\u2019ndan daha da uzakla\u015fm\u0131\u015ft\u0131r. Fotonun g\u00f6zlemcinin g\u00f6z\u00fcne ula\u015ft\u0131\u011f\u0131 anda X g\u00f6kadas\u0131yla Samanyolu\u2019nun aras\u0131ndaki uzakl\u0131k 18 milyar \u0131\u015f\u0131k y\u0131l\u0131na \u00e7\u0131km\u0131\u015ft\u0131r.<\/figcaption><\/figure>\n

Bu hesaplama y\u00f6ntemiyle g\u00f6zlemlenebilir Evren\u2019in b\u00fcy\u00fckl\u00fc\u011f\u00fc hesaplanm\u0131\u015ft\u0131r. I\u015f\u0131\u011f\u0131 13,7 milyar y\u0131l \u00f6nce yola \u00e7\u0131km\u0131\u015f ve g\u00f6z\u00fcm\u00fcze ula\u015ft\u0131\u011f\u0131n\u0131 d\u00fc\u015f\u00fcnd\u00fc\u011f\u00fcm\u00fcz bir nesnenin \u015fu anki uzakl\u0131\u011f\u0131 46 milyar \u0131\u015f\u0131k y\u0131l\u0131d\u0131r. Bir ba\u015fka deyi\u015fle g\u00f6zlemlenebilir Evren\u2019in (balonun) yar\u0131\u00e7ap\u0131 46 milyar \u0131\u015f\u0131k y\u0131l\u0131d\u0131r. Dolay\u0131s\u0131yla g\u00f6rd\u00fc\u011f\u00fcm\u00fcz b\u00fct\u00fcn g\u00f6kadalar ger\u00e7ekte (\u015fu anda) 92 milyar \u0131\u015f\u0131k y\u0131l\u0131 \u00e7ap\u0131 olan bir k\u00fcrenin i\u00e7inde yer almaktad\u0131r. Ama en uza\u011f\u0131 bize 13,7 milyar \u0131\u015f\u0131k y\u0131l\u0131 \u00f6tedeymi\u015f gibi g\u00f6r\u00fcn\u00fcr.<\/p>\n

Kaynak:<\/strong> \u00c7a\u011flar Sunay, 50 Soruda Evren, Bilim ve Gelecek Kitapl\u0131\u011f\u0131, Ekim 2011, s.211-213<\/p>\n","protected":false},"excerpt":{"rendered":"

\u00c7ocuklu\u011fumuzda g\u00f6ky\u00fcz\u00fcne bakt\u0131\u011f\u0131m\u0131zda akl\u0131ma ilk gelen sorulardan biridir evrenin b\u00fcy\u00fckl\u00fc\u011f\u00fc. Akl\u0131m\u0131z ve yorumlar\u0131m\u0131z ise ya\u015fad\u0131\u011f\u0131m\u0131z d\u00fcnyan\u0131n nesneleri ile yan\u0131tlar arama yolundad\u0131r. Neredeyse t\u00fcm insanl\u0131\u011f\u0131n merak etti\u011fi bir soru olarak Evren ne kadar b\u00fcy\u00fckt\u00fcr? Soruya \u00c7a\u011flar Sunay\u2019\u0131n Bilim ve Gelecek Kitapl\u0131\u011f\u0131 i\u00e7in haz\u0131rlam\u0131\u015f oldu\u011fu “50 Soruda Evren” kitab\u0131ndan yan\u0131tlar arad\u0131k. 1838\u2019de Alman g\u00f6kbilimci Friedrich Bessel yak\u0131n […]<\/p>\n","protected":false},"author":185,"featured_media":37764,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[19],"tags":[5474,5473,657,5470,2000,5471,5472],"class_list":["post-37763","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-bilim-gundemi","tag-andromeda","tag-buyukluk","tag-evren","tag-friedrich-bessel","tag-gokbilim","tag-smanyolu","tag-uzaklik"],"acf":[],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t