{"id":27990,"date":"2018-08-07T06:00:17","date_gmt":"2018-08-07T03:00:17","guid":{"rendered":"https:\/\/bilimvegelecek.com.tr\/?p=27990"},"modified":"2018-11-18T14:11:59","modified_gmt":"2018-11-18T11:11:59","slug":"evren-kac-yasinda","status":"publish","type":"post","link":"https:\/\/bilimvegelecek.com.tr\/index.php\/2018\/08\/07\/evren-kac-yasinda","title":{"rendered":"Evren ka\u00e7 ya\u015f\u0131nda?"},"content":{"rendered":"

S\u0131radan bir insan\u0131n zaman alg\u0131s\u0131 olduk\u00e7a s\u0131n\u0131rl\u0131d\u0131r. \u00d6l\u00e7\u00fct\u00fc kendi ya\u015f\u0131 ya da ortalama bir insan \u00f6mr\u00fc olan birisi i\u00e7in milyonlarca insan \u00f6mr\u00fcne denk gelen evrenin ya\u015f\u0131n\u0131 alg\u0131lamak \u00e7ok zordur. Peki evren ka\u00e7 ya\u015f\u0131nda ve evrenin ya\u015f\u0131 nas\u0131l hesaplan\u0131yor?<\/p>\n

\u00c7a\u011flar Sunay, 50 Soruda Evren<\/em><\/a> ba\u015fl\u0131kl\u0131 kitab\u0131nda bu soruya \u015f\u00f6yle yan\u0131t veriyor: (1)<\/p>\n

\u201cEvren ka\u00e7 ya\u015f\u0131ndad\u0131r?\u201d<\/strong>
\n\u201c\u00c7ok de\u011fil 20 y\u0131l \u00f6nce Evren\u2019in ya\u015f\u0131n\u0131n 10-20 milyar aras\u0131nda oldu\u011fu s\u00f6ylenirdi. \u00c7\u00fcnk\u00fc B\u00fcy\u00fck Patlama\u2019n\u0131n ger\u00e7ekle\u015fti\u011fi tarih ancak bu d\u00fczeyde bir kesinlikle hesaplanabiliyordu. 1990\u2019l\u0131 y\u0131llar\u0131n sonunda kesinlik biraz daha artt\u0131 ve 12-15 milyar aral\u0131\u011f\u0131na gelindi. Ocak 2003\u2019ten bu yana Evren\u2019in ya\u015f\u0131n\u0131n ka\u00e7 oldu\u011fundan neredeyse eminiz. Bu \u00e7ok de\u011ferli veriyi Wilkinson Mikrodalga Anizotropi Sondas\u0131\u2019na (WMAP) bor\u00e7luyuz. Onun ta\u015f\u0131d\u0131\u011f\u0131 ayg\u0131tlar\u0131n mikrodalga \u0131\u015f\u0131mas\u0131ndaki s\u0131cakl\u0131k de\u011fi\u015fimlerine dayanarak \u00e7\u0131kartt\u0131\u011f\u0131 Evren haritas\u0131 sayesinde, Evren\u2019in yaln\u0131zca ya\u015f\u0131na de\u011fil, geni\u015fleme h\u0131z\u0131na, hatta temel i\u00e7eriklerine ili\u015fkin de olduk\u00e7a duyarl\u0131 veriler elde edilmi\u015ftir.<\/p>\n

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Evrenin ya\u015f\u0131n\u0131n grafiksel g\u00f6sterimi<\/figcaption><\/figure>\n

\u201cEvren\u2019imizin geni\u015fledi\u011finin yakla\u015f\u0131k 90 y\u0131ld\u0131r fark\u0131nday\u0131z. Art\u0131k geni\u015fleme h\u0131z\u0131n\u0131 da olduk\u00e7a \u201ckesin\u201d biliyoruz. Evren\u2019in bug\u00fcnk\u00fc geni\u015fleme h\u0131z\u0131n\u0131 ge\u00e7mi\u015fe y\u00f6nelik kullanarak, B\u00fcy\u00fck Patlama\u2019n\u0131n g\u00fcn\u00fcm\u00fczden ne kadar zaman \u00f6nce oldu\u011funu hesaplayabiliyoruz. G\u00f6kbilimciler Evren\u2019in geni\u015fleme h\u0131z\u0131n\u0131 Hubble De\u011fi\u015fkeni (eskiden Hubble Sabiti denirdi) diye adland\u0131rd\u0131klar\u0131 bir say\u0131yla anlat\u0131rlar.<\/p>\n

\u201cHubble De\u011fi\u015fkeni, g\u00f6kadalar\u0131n uzakl\u0131klar\u0131yla h\u0131zlar\u0131 aras\u0131ndaki ili\u015fkiyi ortaya koyar ve\u00a0H0<\/sub> simgesiyle g\u00f6sterilir.<\/p>\n

\"\"<\/p>\n

\u201cEvren\u2019in geni\u015fleme h\u0131z\u0131 zaman i\u00e7inde de\u011fi\u015fmi\u015ftir. O nedenle H0<\/sub>\u2019daki s\u0131f\u0131r, de\u011fi\u015fkenin g\u00fcn\u00fcm\u00fczdeki de\u011ferini g\u00f6stermek i\u00e7in kullan\u0131l\u0131r. De\u011fi\u015fkenin de\u011ferini belirlemek olduk\u00e7a zordur; \u00e7\u00fcnk\u00fc g\u00f6kadalar aras\u0131 uzakl\u0131klar\u0131n \u00f6l\u00e7\u00fcm\u00fcne dayan\u0131r. G\u00f6kadalar aras\u0131 uzakl\u0131klar\u0131 duyarl\u0131 bir \u015fekilde \u00f6l\u00e7mek de ger\u00e7ekten zor bir i\u015ftir.<\/p>\n

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Yukar\u0131daki grafikte g\u00f6kadalar aras\u0131 uzakl\u0131klar\u0131n art\u0131\u015f\u0131n\u0131n -Evren\u2019in geni\u015fleme h\u0131z\u0131n\u0131n- zamanla de\u011fi\u015fimi g\u00f6r\u00fcl\u00fcyor. Geni\u015fleme sabit bir h\u0131zla (22 km\/s\/milyon \u0131\u015f\u0131k y\u0131l\u0131) olsayd\u0131, Evren\u2019in ya\u015f\u0131 13,5 milyar olacakt\u0131; e\u011fer ge\u00e7mi\u015ften azalarak gelip, azalarak devam etseydi, o zaman Evren\u2019in ya\u015f\u0131n\u0131n 13,5 milyardan k\u00fc\u00e7\u00fck olmas\u0131 gerekecekti; e\u011fer artarak gelip, artmaya devam etseydi, o zaman da 13,5 milyardan daha ya\u015fl\u0131 olmas\u0131 gerekirdi. Ne var ki bu \u00fc\u00e7 senaryo da ger\u00e7ekle\u015fmemi\u015ftir. Ger\u00e7ekle\u015fen durum geni\u015fleme h\u0131z\u0131n\u0131n belli d\u00f6nemlerde artt\u0131\u011f\u0131 belli d\u00f6nemlerde de azald\u0131\u011f\u0131 karma bir durumdur.<\/figcaption><\/figure>\n

\u201cEdwin Hubble\u2019\u0131n kendi g\u00f6zlemlerine dayanarak buldu\u011fu ilk de\u011fer 150 km\/s\/milyon \u0131\u015f\u0131k y\u0131l\u0131yd\u0131. 1994\u2019te Hubble Uzay Teleskopu\u2019nun, yak\u0131n bir g\u00f6kadaya y\u00f6nelik g\u00f6zlemleri sonucunda 24,5 km\/s\/milyon \u0131\u015f\u0131k y\u0131l\u0131 oldu\u011fu hesaplanm\u0131\u015ft\u0131. En son g\u00f6zlemler do\u011frultusunda Hubble De\u011fi\u015fkeni\u2019nin 22\u00b12 km\/s\/milyon \u0131\u015f\u0131k y\u0131l\u0131 oldu\u011fu kabul ediliyor. Bu \u015fu anlama gelir: On milyon \u0131\u015f\u0131k y\u0131l\u0131 \u00f6tedeki bir g\u00f6kada, bizden saniyede 220 km\u2019lik bir h\u0131zla uzakla\u015f\u0131r; 20 milyon \u0131\u015f\u0131k y\u0131l\u0131 \u00f6tedeki bir g\u00f6kadaysa saniyede 440 km\u2019lik bir h\u0131zla uzakla\u015f\u0131r; 300 milyon \u0131\u015f\u0131k y\u0131l\u0131 \u00f6tedeki bir g\u00f6kada da saniyede 6600 km\u2019lik bir h\u0131zla uzakla\u015f\u0131r. Hubble De\u011fi\u015fkeni\u2019nden yararlanarak yap\u0131lan basit hesapla (Hubble De\u011fi\u015fkeni\u2019nin tersi, do\u011frudan Evren\u2019in -kabaca- ya\u015f\u0131n\u0131 verir), Evren\u2019deki her \u015feyin tek bir noktada topland\u0131\u011f\u0131 an\u0131n, yani B\u00fcy\u00fck Patlama an\u0131n\u0131n g\u00fcn\u00fcm\u00fczden 13,5 milyar y\u0131l \u00f6nce ger\u00e7ekle\u015fti\u011fi sonucuna ula\u015f\u0131l\u0131r. Bir ba\u015fka deyi\u015fle Evren\u2019imiz 13,5 milyar ya\u015f\u0131ndad\u0131r.<\/p>\n

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\u00dcstteki grafikte Evren\u2019in geni\u015fleme h\u0131z\u0131n\u0131n zaman i\u00e7indeki de\u011fi\u015fimi g\u00f6r\u00fcl\u00fcrken alttaki grafikte de buna kar\u015f\u0131l\u0131k gelen uzakl\u0131k art\u0131\u015f\u0131 g\u00f6r\u00fcl\u00fcyor. Buna g\u00f6re bug\u00fcn 22 km\/s\/milyon \u0131\u015f\u0131k y\u0131l\u0131 olan Evren\u2019in geni\u015fleme h\u0131z\u0131, gelecekte daha da artacak ve g\u00f6kadalar birbirlerinden daha h\u0131zl\u0131 uzakla\u015facak. 1999\u2019da ortaya \u00e7\u0131kan bu olgu asl\u0131nda bilim insanlar\u0131n\u0131n \u00e7o\u011funun kar\u015f\u0131la\u015fmay\u0131 hi\u00e7 beklemedi\u011fi bir olguydu. Onlar Evren\u2019in geni\u015flemesinin s\u00fcrece\u011fini, ama geni\u015fleme h\u0131z\u0131n\u0131n ya azalaca\u011f\u0131n\u0131 ya da sabit kalaca\u011f\u0131n\u0131 bulmay\u0131 umuyorlard\u0131.<\/figcaption><\/figure>\n

\u201cAncak bu hesap, b\u00fcy\u00fck bir \u00f6n kabul ile birlikte yap\u0131lm\u0131\u015ft\u0131r. O da Evren\u2019in geni\u015fleme h\u0131z\u0131n\u0131n Evren\u2019in ba\u015flang\u0131c\u0131ndan bu yana hep ayn\u0131 oldu\u011fu \u00f6n kabul\u00fcd\u00fcr. Halbuki Evren\u2019in geni\u015fleme h\u0131z\u0131 zamanla de\u011fi\u015fmi\u015f olabilir, ki ger\u00e7ekten de de\u011fi\u015fmi\u015ftir. G\u00f6kbilimciler Evren\u2019in ge\u00e7mi\u015fte bir d\u00f6nem \u00e7ok h\u0131zl\u0131 geni\u015fledi\u011fini, sonra bu h\u0131z\u0131n yava\u015flay\u0131p bug\u00fcnk\u00fc d\u00fczeyinin de alt\u0131na indi\u011fini ve sonra yeniden artt\u0131\u011f\u0131n\u0131 bulmu\u015flard\u0131r. Ge\u00e7mi\u015fte Evren\u2019in geni\u015fleme h\u0131z\u0131n\u0131n d\u00fc\u015f\u00fck ve y\u00fcksek oldu\u011fu d\u00f6nemlerin asl\u0131nda birbirine yak\u0131n uzunlukta oldu\u011fu ortaya \u00e7\u0131km\u0131\u015ft\u0131r. Sonu\u00e7ta yap\u0131lan hesaplara g\u00f6re B\u00fcy\u00fck Patlama\u2019n\u0131n g\u00fcn\u00fcm\u00fczden 13,75\u00b10,11 milyar y\u0131l \u00f6nce oldu\u011fu anla\u015f\u0131lm\u0131\u015ft\u0131r. Bir ba\u015fka deyi\u015fle Evren\u2019imizin ya\u015f\u0131 13,75 milyard\u0131r.\u201d<\/p>\n

Kaynak:<\/strong>
\n1) Sunay, \u00c7a\u011flar, 50 Soruda Evren<\/em>, Bilim ve Gelecek Kitapl\u0131\u011f\u0131, \u0130stanbul, 2011, ss. 217-219.<\/p>\n","protected":false},"excerpt":{"rendered":"

S\u0131radan bir insan\u0131n zaman alg\u0131s\u0131 olduk\u00e7a s\u0131n\u0131rl\u0131d\u0131r. \u00d6l\u00e7\u00fct\u00fc kendi ya\u015f\u0131 ya da ortalama bir insan \u00f6mr\u00fc olan birisi i\u00e7in milyonlarca insan \u00f6mr\u00fcne denk gelen evrenin ya\u015f\u0131n\u0131 alg\u0131lamak \u00e7ok zordur. Peki evren ka\u00e7 ya\u015f\u0131nda ve evrenin ya\u015f\u0131 nas\u0131l hesaplan\u0131yor? \u00c7a\u011flar Sunay, 50 Soruda Evren ba\u015fl\u0131kl\u0131 kitab\u0131nda bu soruya \u015f\u00f6yle yan\u0131t veriyor: (1) \u201cEvren ka\u00e7 ya\u015f\u0131ndad\u0131r?\u201d \u201c\u00c7ok […]<\/p>\n","protected":false},"author":453,"featured_media":27992,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[26,3624],"tags":[248,657,2000,3786,3787],"class_list":["post-27990","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-fizik","category-sorularla-bilim","tag-astronomi","tag-evren","tag-gokbilim","tag-hubble-degiskeni","tag-hubble-uzay-teleskobu"],"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