Carnegie ve Chicago \u00dcniversitesi\u2019nden g\u00f6revlilerin olu\u015fturdu\u011fu bir ara\u015ft\u0131rma grubu, evrenin ne denli h\u0131zl\u0131 geni\u015fledi\u011fiyle ilgili yepyeni bir \u00f6l\u00e7\u00fcm yapmak i\u00e7in Hubble Uzay Teleskopu taraf\u0131ndan g\u00f6zlemlenen k\u0131rm\u0131z\u0131 dev y\u0131ld\u0131zlar\u0131 kulland\u0131 ve ard\u0131ndan kendilerini hararetli bir tart\u0131\u015fman\u0131n i\u00e7ine att\u0131lar. Ara\u015ft\u0131rman\u0131n \u2013daha \u00f6nce dile getirilen ve iki rakip de\u011fer aras\u0131nda bir yere denk d\u00fc\u015fen- ayr\u0131nt\u0131l\u0131 sonu\u00e7lar\u0131 \u2018The Astrophysical Journal\u2019 adl\u0131 dergide yay\u0131nlanacak.<\/p>\n
Yakla\u015f\u0131k bir as\u0131r \u00f6nce, Carnegie\u2019de \u00e7al\u0131\u015fan g\u00f6kbilimci Edwin Hubble, evrenin B\u00fcy\u00fck Patlama\u2019yla birlikte ortaya \u00e7\u0131kmas\u0131ndan beridir s\u00fcrekli bi\u00e7imde b\u00fcy\u00fcd\u00fc\u011f\u00fcn\u00fc ke\u015ffetti. \u00d6te yandan, tam olarak hangi h\u0131zla hareket etti\u011fi \u2013ke\u015ffin \u015ferefine \u2018Hubble Sabiti\u2019 diye adland\u0131r\u0131lan bir de\u011fer- \u0131srarla belirsizli\u011fini korudu.<\/p>\n
Hubble Sabiti, bilim insanlar\u0131n\u0131n evrenin ge\u00e7mi\u015fini ve yap\u0131s\u0131n\u0131 ortaya \u00e7\u0131karmalar\u0131na yard\u0131mc\u0131 oldu ve bu de\u011ferle ilgili yap\u0131lacak do\u011fru bir \u00f6l\u00e7\u00fcm, bu hakim modeldeki herhangi bir hatay\u0131 g\u00f6zler \u00f6n\u00fcne serebilir.<\/p>\n
Mesle\u011fine Carnegie \u00dcniversitesi\u2019nde ba\u015flay\u0131p \u015fimdi Chicago \u00dcniversitesi\u2019nde g\u00f6revli olan ara\u015ft\u0131rma ba\u015fyazar\u0131 Wendy Freedman, \u201cHubble Sabiti, evrenin mutlak \u00f6l\u00e7e\u011fini, boyutunu ve ya\u015f\u0131n\u0131 tespit eden kozmolojik bir parametre; bu sabit, evrenin nas\u0131l geli\u015fti\u011fini \u00f6l\u00e7menin en do\u011frudan yollar\u0131ndan biri,\u201d diyor.<\/p>\n
Bug\u00fcne dek, evrenin geni\u015fleme oran\u0131n\u0131 \u00f6l\u00e7mek amac\u0131yla kulland\u0131\u011f\u0131m\u0131z iki temel ara\u00e7 mevcuttu. Maalesef iki y\u00f6ntemin ula\u015ft\u0131\u011f\u0131 sonu\u00e7lar ayn\u0131 de\u011fil ve her iki taraf da git gide daha hassas okumalar yap\u0131yor olsa da iki say\u0131 aras\u0131ndaki uyu\u015fmazl\u0131k s\u00fcr\u00fcyor. Bununla beraber, iki de\u011fer aras\u0131ndaki fark\u0131n, y\u00f6ntemlerden biri ya da her ikisindeki sistem temelli hatalardan kaynaklan\u0131yor olmas\u0131 ve ara\u015ft\u0131rma ekibini yeni tekniklerini geli\u015ftirmeleri i\u00e7in te\u015fvik etmesi m\u00fcmk\u00fcn g\u00f6r\u00fcn\u00fcyor.<\/p>\n
Carnegie grubuna yol g\u00f6steren y\u00f6ntem, d\u00fczenli aral\u0131klarla titre\u015fen \u2018Sefeid\u2019 ad\u0131 verilen y\u0131ld\u0131zlar\u0131 kullan\u0131yor. Y\u0131ld\u0131zlar\u0131n (t\u0131pk\u0131 kalbimizde oldu\u011fu gibi) nab\u0131z h\u0131zlar\u0131n\u0131n (parlay\u0131p-s\u00f6nme aral\u0131\u011f\u0131n\u0131n) kendi i\u00e7 parlakl\u0131klar\u0131yla ba\u011flant\u0131l\u0131 oldu\u011fu bilindi\u011fi i\u00e7in, g\u00f6kbilimciler D\u00fcnya\u2019ya olan uzakl\u0131klar\u0131n\u0131 \u00f6l\u00e7mek amac\u0131yla parlakl\u0131klar\u0131n\u0131 ve nab\u0131z at\u0131\u015flar\u0131 aras\u0131nda ge\u00e7en s\u00fcreyi kullanabiliyorlar.<\/p>\n
Makalenin ortak yazarlar\u0131ndan Carnegie\u2019de g\u00f6revli Barry Madore \u201cUzaklardan bakt\u0131\u011f\u0131m\u0131z iki zil ayn\u0131 gibi g\u00f6r\u00fcnebilir; fakat onlar\u0131n seslerini dinlemek, birinin \u00e7ok daha b\u00fcy\u00fck ve uzakta, di\u011ferininse daha k\u00fc\u00e7\u00fck ve yak\u0131nda oldu\u011funu ortaya \u00e7\u0131karabilir,\u201d diyor. \u201cAyn\u0131 bi\u00e7imde, uzaktaki Sefeidlerin ne oranda parlad\u0131\u011f\u0131n\u0131 ve yak\u0131ndaki Sefeidlerin parlakl\u0131\u011f\u0131na k\u0131yasla nas\u0131l g\u00f6r\u00fcnd\u00fc\u011f\u00fcn\u00fc kar\u015f\u0131la\u015ft\u0131rmak, y\u0131ld\u0131zlar\u0131n par\u00e7as\u0131 oldu\u011fu ev sahibi galaksilerin D\u00fcnya\u2019dan ne kadar uzakta oldu\u011funu tespit etmemizi sa\u011flar.\u201d
\nBir kez g\u00f6kcisminin mesafesini anlad\u0131\u011f\u0131m\u0131zda, bizden hangi h\u0131zla uzakla\u015ft\u0131\u011f\u0131n\u0131n \u00f6l\u00e7\u00fclmesi, evrenin geni\u015fleme h\u0131z\u0131n\u0131 da a\u00e7\u0131\u011fa \u00e7\u0131kar\u0131r. Bu iki de\u011ferin oran\u0131 -mesafeye b\u00f6l\u00fcnen h\u0131z- ise bizlere Hubble Sabiti\u2019ni verir.<\/p>\n
\u0130kinci y\u00f6ntem, B\u00fcy\u00fck Patlama\u2019dan geriye kalan son parlamay\u0131 kullan\u0131r. \u2018Kozmik arka plan radyasyonu\u2019 denilen bu \u015fey, g\u00f6rebildi\u011fimiz en eski \u0131\u015f\u0131\u011f\u0131n kal\u0131nt\u0131s\u0131d\u0131r. Bebek evreninin i\u00e7inde bulundu\u011fu yo\u011fun, \u00e7orba k\u0131vam\u0131ndaki plazmada s\u0131k\u0131\u015ft\u0131rma kal\u0131plar\u0131 h\u00e2l\u00e2 hafif d\u00fczeyde \u0131s\u0131 de\u011fi\u015fimleri halinde g\u00f6r\u00fclebilir ve haritaland\u0131r\u0131labilir. Evrenin ilk birka\u00e7 dakikas\u0131n\u0131 belgeleyen bu \u0131s\u0131 dalgalanmalar\u0131, bir model arac\u0131l\u0131\u011f\u0131yla zamanda ilerletilebilir ve g\u00fcn\u00fcm\u00fczde Hubble Sabiti\u2019ni tahmin etmek amac\u0131yla kullan\u0131labilir.
\nEski teknik, evrenin geni\u015fleme oran\u0131n\u0131n, megaparsek* ba\u015f\u0131na saniyede 74.0 kilometre oldu\u011funu \u00f6ne s\u00fcr\u00fcyor; ikinci teknik ise 67.4 oldu\u011funu ifade ediyor. E\u011fer bu ger\u00e7ekse, tutars\u0131zl\u0131k hali fizik alan\u0131nda yeni bir yakla\u015f\u0131m\u0131n\u0131n habercisi olabilir.<\/p>\n
Freedman \u00f6nc\u00fcl\u00fc\u011f\u00fcnde ara\u015ft\u0131rmalar\u0131n\u0131 s\u00fcrd\u00fcren ve Carnegie \u00dcniversitesi g\u00f6kbilimcileri Barry Madore, Christopher Burns, Mark Phillips, Jeff Rich ve Mark Seibert\u2019i de i\u00e7eren Carnegie-Chicago Hubble Program\u0131 grubu ve ayr\u0131ca Carnegie ve Princeton \u00dcniversitelerinde \u00f6\u011fretim \u00fcyesi olan Rachael Beaton, birlikte Hubble Sabiti\u2019ni hesaplamak do\u011frultusunda yeni bir y\u00f6ntem geli\u015ftirdiler.<\/p>\n
Kulland\u0131klar\u0131 teknik, \u2018k\u0131rm\u0131z\u0131 dev\u2019 ad\u0131 verilen a\u015f\u0131r\u0131 parlak bir y\u0131ld\u0131z t\u00fcr\u00fcne odaklan\u0131yor. Bu y\u0131ld\u0131zlar\u0131n i\u00e7erdi\u011fi helyum, hayat d\u00f6ng\u00fclerinin belirli bir a\u015famas\u0131nda tutu\u015fur ve bu yeni enerji kayna\u011f\u0131 taraf\u0131ndan y\u0131ld\u0131zlar\u0131n yap\u0131lar\u0131 \u00e7ekirdek k\u0131sm\u0131nda yeniden d\u00fczenlenir.<\/p>\n
Madore, \u201cBir dalg\u0131\u00e7ku\u015funun \u00e7\u0131\u011fl\u0131\u011f\u0131n\u0131n di\u011fer ku\u015f c\u0131v\u0131lt\u0131lar\u0131 aras\u0131nda hemen fark edilebilir olmas\u0131 gibi, bizim durumumuzda k\u0131rm\u0131z\u0131 bir devin tepe noktadaki parlakl\u0131\u011f\u0131 da kolayca fark edilebilir,\u201d diyor. \u201cBu halleri onlar\u0131 kusursuz \u2018standart mumlar\u2019** haline getiriyor.\u201d<\/p>\n
Ara\u015ft\u0131rma grubu, yak\u0131nlarda bulunan galaksilerdeki k\u0131rm\u0131z\u0131 devleri aramak i\u00e7in Hubble Uzay Teleskopu\u2019nun hassas kameralar\u0131n\u0131 kulland\u0131.<\/p>\n
Burns, \u201cBunu, helyum patlamas\u0131 ya\u015fayan en parlak k\u0131rm\u0131z\u0131 deve benzer bi\u00e7imde, en uzun boylu ki\u015fiyi tan\u0131mlamak amac\u0131yla bir kalabal\u0131\u011f\u0131 taramak gibi farz edin,\u201d diyor. \u201cHerhangi bir odada bulunan en uzun boylu ki\u015finin tam olarak hangi uzunlukta oldu\u011funu bildi\u011finiz bir d\u00fcnyada ya\u015f\u0131yorsan\u0131z, -en parlak k\u0131rm\u0131z\u0131 devin parlakl\u0131\u011f\u0131n\u0131n tepe noktas\u0131n\u0131n da benzer oldu\u011funu varsayarsak- sahip oldu\u011fumuz bilgiyi bizden ne kadar uzakta oldu\u011funu tespit etmek i\u00e7in kullanabilirsiniz.\u201d<\/p>\n
Bu yeni ke\u015ffedilen k\u0131rm\u0131z\u0131 devlerle aram\u0131zdaki mesafeyi \u00f6\u011frenmemizin ard\u0131ndan, Hubble Sabiti, k\u0131rm\u0131z\u0131 devlerin bize olan yak\u0131nl\u0131\u011f\u0131n\u0131n yol a\u00e7t\u0131\u011f\u0131 belirsizli\u011fi azaltmak ve daha uzak Hubble verilerine eri\u015fmemizi sa\u011flamak amac\u0131yla, di\u011fer bir standart mum tipi olan \u2018IA S\u00fcpernova\u2019 yard\u0131m\u0131yla hesaplanabilir.<\/p>\n
K\u0131rm\u0131z\u0131 dev y\u00f6ntemine g\u00f6re, evrenin geni\u015fleme oran\u0131 69.8\u2019dir ve k\u0131\u015fk\u0131rt\u0131c\u0131 bir bi\u00e7imde daha \u00f6nce belirlenmi\u015f olan iki say\u0131n\u0131n aras\u0131nda bir yere denk d\u00fc\u015fer.<\/p>\n
Madore, \u201cBu, eskilerin me\u015fhur \u2018Seninle Arada S\u0131k\u0131\u015f\u0131p Kald\u0131k\u2019adl\u0131 \u015fark\u0131s\u0131na benziyor\u201d diye \u015faka yap\u0131yor. \u201cPeki, g\u00f6kbilim alan\u0131nda bir kriz mi var? Biz var olan e\u015fitli\u011fi bozan taraf olmay\u0131 umuyorduk ama \u015fimdilik cevab\u0131m\u0131z \u015fu olacak: O kadar \u00e7abuk de\u011fil. Evrenin standart modelinin tamamlan\u0131p tamamlanmad\u0131\u011f\u0131 sorusu hen\u00fcz yan\u0131tlanmaya devam ediyor.\u201d<\/p>\n
Ara\u015ft\u0131rman\u0131n finansman\u0131, NASA arac\u0131l\u0131\u011f\u0131yla Astronomi Ara\u015ft\u0131rmalar\u0131 yapan \u00dcniversiteler Birli\u011fi taraf\u0131ndan i\u015fletilen Uzay Teleskopu Bilim Enstit\u00fcs\u00fc\u2019nden sunulan bir hibeyle sa\u011fland\u0131: Di\u011fer kat\u0131l\u0131mc\u0131lar ABD Ulusal Bilim Vakf\u0131, Kore H\u00fck\u00fcmeti taraf\u0131ndan finanse edilen Kore Ulusal Ara\u015ft\u0131rma Vakf\u0131, Hubble verilerini payla\u015fan NASA, Carnegie Bilim Kurumu ve Chicago \u00dcniversitesi oldu.<\/p>\n
Bu \u00e7al\u0131\u015fma i\u00e7in kullan\u0131lan bilgi-i\u015flem kaynaklar\u0131, Ahmanson Vakf\u0131\u2019ndan yap\u0131lan bir hibeyle m\u00fcmk\u00fcn oldu. Ara\u015ft\u0131rma, NASA ile yap\u0131lan s\u00f6zle\u015fme kapsam\u0131nda Kaliforniya Teknoloji Enstit\u00fcs\u00fc\u2019n\u00fcn Jet \u0130ti\u015f Laboratuvar\u0131 taraf\u0131ndan i\u015fletilen NASA \/ IPAC Extragalaktik veri taban\u0131ndan faydaland\u0131. Bu makalede sunulan kimi verilerse Mikulski Uzay Teleskoplar\u0131 ar\u015fivinden elde edildi.<\/p>\n
Kaynak: Gazete Duvar<\/p>\n","protected":false},"excerpt":{"rendered":"
Carnegie ve Chicago \u00dcniversitesi\u2019nden g\u00f6revlilerin olu\u015fturdu\u011fu bir ara\u015ft\u0131rma grubu, evrenin ne denli h\u0131zl\u0131 geni\u015fledi\u011fiyle ilgili yepyeni bir \u00f6l\u00e7\u00fcm yapmak i\u00e7in Hubble Uzay Teleskopu taraf\u0131ndan g\u00f6zlemlenen k\u0131rm\u0131z\u0131 dev y\u0131ld\u0131zlar\u0131 kulland\u0131 ve ard\u0131ndan kendilerini hararetli bir tart\u0131\u015fman\u0131n i\u00e7ine att\u0131lar. Ara\u015ft\u0131rman\u0131n \u2013daha \u00f6nce dile getirilen ve iki rakip de\u011fer aras\u0131nda bir yere denk d\u00fc\u015fen- ayr\u0131nt\u0131l\u0131 sonu\u00e7lar\u0131 \u2018The Astrophysical […]<\/p>\n","protected":false},"author":23,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":""},"categories":[506],"tags":[],"class_list":["post-103374","post","type-post","status-publish","format-standard","hentry","category-astronomi"],"acf":[],"yoast_head":"\n