{"id":33876,"date":"2019-04-19T03:00:21","date_gmt":"2019-04-19T00:00:21","guid":{"rendered":"https:\/\/bilimvegelecek.com.tr\/?p=33876"},"modified":"2019-04-19T02:03:54","modified_gmt":"2019-04-18T23:03:54","slug":"33876","status":"publish","type":"post","link":"https:\/\/bilimvegelecek.com.tr\/index.php\/2019\/04\/19\/33876","title":{"rendered":"Her\u015feye kadir fizik 2674 \u0131\u015f\u0131k y\u0131l\u0131 uzakl\u0131ktaki y\u0131ld\u0131z\u0131n \u00e7ap\u0131n\u0131 nas\u0131l \u00f6l\u00e7t\u00fc?"},"content":{"rendered":"

Gece g\u00f6ky\u00fcz\u00fcne bakt\u0131\u011f\u0131m\u0131zda g\u00f6rd\u00fc\u011f\u00fcm\u00fcz y\u0131ld\u0131zlar hakk\u0131nda pek \u00e7ok \u015fey s\u00f6yleyebiliriz: Konumlar\u0131, uzakl\u0131klar\u0131, hatta s\u0131cakl\u0131klar\u0131\u2026 Ancak aradaki mesafeden dolay\u0131 boyutlar\u0131n\u0131 tam olarak bilmek m\u00fcmk\u00fcn de\u011fil diye d\u00fc\u015f\u00fcn\u00fcr\u00fcz. Oysa g\u00f6r\u00fcnen o ki, m\u00fcmk\u00fcn olmayan, cevab\u0131 olan sorular\u0131n g\u00fcn\u00fcn birinde yan\u0131t bulmamas\u0131ym\u0131\u015f. Zira <\/span>Nature Astronomy<\/span><\/i> dergisinin 15 Nisan say\u0131s\u0131nda yay\u0131mlanan, 23 \u00fcniversiteden uluslararas\u0131 bir ekibin \u00e7e\u015fitli evrelerine dahil oldu\u011fu yeni bir \u00e7al\u0131\u015fmada, teleskopumuza \u00e7arpan en uzak y\u0131ld\u0131z\u0131n dahi tam b\u00fcy\u00fckl\u00fc\u011f\u00fcn\u00fc s\u00f6ylemenin art\u0131k m\u00fcmk\u00fcn oldu\u011fu belirtiliyor.<\/span><\/p>\n

Samanyolu Galaksisi\u2019nde 100 milyardan fazla y\u0131ld\u0131z bulundu\u011fu tahmin ediliyor. G\u00fcne\u015f\u2019i saymazsak bunlardan en yak\u0131n olan\u0131n\u0131n uzakl\u0131\u011f\u0131 d\u00f6rt \u0131\u015f\u0131k y\u0131l\u0131ndan yani 25 trilyon milden fazla. Ancak bu mesafe, Arizona\u2019daki Fred Lawrence Whipple G\u00f6zlemevi\u2019nde bulunan \u00e7ok \u00f6zel d\u00f6rt teleskop i\u00e7in \u00e7ocuk oyunca\u011f\u0131. \u00c7\u00fcnk\u00fc Very Energetic Radiation Imaging Telescope Array System\u2019\u0131n (VERITAS), ya da T\u00fcrk\u00e7ele\u015ftirirsek, Y\u00fcksek Enerjili Radyasyon G\u00f6r\u00fcnt\u00fcleme Teleskobu Array Sistemi\u2019nin enini boyunu bildirdi\u011fi devasa y\u0131ld\u0131z\u0131n uzakl\u0131\u011f\u0131 tahayy\u00fcl s\u0131n\u0131rlar\u0131n\u0131 zorluyor: 2674 \u0131\u015f\u0131k y\u0131l\u0131. Teleskoplar buna bir de 700 \u0131\u015f\u0131k y\u0131l\u0131 uzakl\u0131kta, G\u00fcne\u015f benzeri bir y\u0131ld\u0131z daha eklemi\u015f; kendisi gece g\u00f6r\u00fclebilecek y\u0131ld\u0131zlar aras\u0131nda en k\u00fc\u00e7\u00fc\u011f\u00fc olma \u00f6zelli\u011fi ta\u015f\u0131yor. Peki normalde, ya da en az\u0131ndan \u015fimdiye kadar, en yak\u0131ndaki y\u0131ld\u0131z\u0131n bile \u00e7ap\u0131 hakk\u0131nda ger\u00e7ek bir rakam vermek muazzam uzakl\u0131\u011f\u0131ndan dolay\u0131 m\u00fcmk\u00fcn de\u011filken, 2674 \u0131\u015f\u0131k y\u0131ll\u0131k bu s\u0131\u00e7rama nereden kaynaklan\u0131yor?<\/span><\/p>\n

En g\u00fc\u00e7l\u00fc optik teleskopun ekran\u0131na dahi bulan\u0131k bir noktac\u0131k gibi yans\u0131yacak olan y\u0131ld\u0131z g\u00f6r\u00fcnt\u00fcs\u00fcnden anatomik sonu\u00e7lar \u00e7\u0131karmak, difraksiyon (k\u0131r\u0131n\u0131m) denen bir optik olguyla m\u00fcmk\u00fcn olmu\u015f. Basit\u00e7e a\u00e7\u0131klamak gerekirse, y\u0131ld\u0131z\u0131n \u00f6n\u00fcnden bir g\u00f6k cismi ge\u00e7ti\u011finde, ok\u00fcltasyon (\u00f6rt\u00fcnme) denen, g\u00f6lgelenme ve g\u00f6lge \u00e7eperindeki \u0131\u015f\u0131k dalgalar\u0131n\u0131n \u015fablonunda de\u011fi\u015fime neden olan bir olay meydana gelir. Mesela her g\u00fcn D\u00fcnya’n\u0131n tepesinden ge\u00e7en asteroidleri d\u00fc\u015f\u00fcn\u00fcn. Bunlar\u0131n silik g\u00f6lgesi m\u00fckemmel keskinlikte hatlara sahip olmaktan \u00e7ok uzakt\u0131r asl\u0131nda. G\u00f6lgenin merkezi, \u0131\u015f\u0131\u011f\u0131n dalga yap\u0131s\u0131ndan dolay\u0131, su harelerine benzer dalgalarla \u00e7evrelenmi\u015f vaziyettedir. Ara\u015ft\u0131rmac\u0131lar, difraksiyon ad\u0131 verilen bu olay\u0131n, yani g\u00f6lgenin kenar\u0131ndaki motiflerin ald\u0131\u011f\u0131 bi\u00e7imin, \u0131\u015f\u0131\u011f\u0131n kayna\u011f\u0131 hakk\u0131nda fikir verebilece\u011fini d\u00fc\u015f\u00fcnm\u00fc\u015fler. Tabii s\u00f6z konusu olan inan\u0131lmaz uzakl\u0131ktaki bir y\u0131ld\u0131z\u0131n \u00f6n\u00fcnden ge\u00e7en asteroidi tam do\u011fru zamanda ve do\u011fru noktada yakalamak olunca i\u015fin i\u00e7ine VERITAS gibi, milisaniye aral\u0131\u011f\u0131yla g\u00f6r\u00fcnt\u00fc alabilen bir aletin girmesi gerekiyor. Ara\u015ft\u0131rma raporunun ifadesiyle VERITAS\u2019\u0131n bu becerisi, Eyfel Kulesi\u2019nin tepesindeki bir bozuk paran\u0131n New York\u2019tan g\u00f6r\u00fclebilmesi gibi bir\u015fey!<\/span><\/p>\n

Makalede belirtildi\u011fine g\u00f6re VERITAS teleskoplar\u0131n\u0131n, TYC 5517-227-1 isimli y\u0131ld\u0131z\u0131n 60 kilometre a\u00e7\u0131\u011f\u0131ndan ge\u00e7en Imprinetta isimli asteroidi net bi\u00e7imde tespit edebildikleri tarih 22 \u015eubat 2018. Muhtemelen gezegenlerin olu\u015ftu\u011fu 4,6 milyar y\u0131l \u00f6ncesinden kalma moloz y\u0131\u011f\u0131n\u0131ndan bir par\u00e7a olan Imprinetta\u2019n\u0131n yaratt\u0131\u011f\u0131 ok\u00fcltasyon sadece birka\u00e7 saniye s\u00fcrm\u00fc\u015f. Ancak bu birka\u00e7 saniyenin her biri, y\u00fczde elli \u015fansla, VERITAS\u2019\u0131n y\u00fczlerce poz almas\u0131 i\u00e7in yetmi\u015f. Gerisi \u00e7orap s\u00f6k\u00fc\u011f\u00fc\u2026 Teleskoplar\u0131n toplad\u0131\u011f\u0131 verilerdeki difraksiyon \u015fablonlar\u0131n\u0131n parlakl\u0131\u011f\u0131ndan yola \u00e7\u0131karak olu\u015fturulan y\u0131ld\u0131z g\u00f6r\u00fcnt\u00fcleri, 2674 \u0131\u015f\u0131k y\u0131l\u0131, yani G\u00fcne\u015f\u2019in D\u00fcnya\u2019ya uzakl\u0131\u011f\u0131n\u0131n 200 milyon kat\u0131 mesafedeki bu devasa g\u00f6kcisminin \u00e7ap\u0131n\u0131n G\u00fcne\u015f\u2019in 11 kat\u0131 oldu\u011fu bilgisini vermi\u015f (ki bu da s\u00f6z konusu y\u0131ld\u0131z\u0131 bir k\u0131rm\u0131z\u0131 dev yapar). Ard\u0131ndan ayn\u0131 i\u015flem 2018 May\u0131s ay\u0131nda, TYC 278-748-1 isimli y\u0131ld\u0131z\u0131n 88 kilometre a\u00e7\u0131\u011f\u0131ndan ge\u00e7en Penelope asteroidi i\u00e7in de tekrarlanm\u0131\u015f. Sonu\u00e7, G\u00fcne\u015f\u2019in \u00e7ap\u0131n\u0131 2,17\u2019ye katlayan G s\u0131n\u0131f\u0131 bir sar\u0131 c\u00fcce y\u0131ld\u0131z. \u0130\u015fin g\u00fczel taraf\u0131, daha \u00f6nce alternatif y\u00f6ntemlerle yap\u0131lan \u00e7ap \u00f6l\u00e7\u00fcmlerinin bu rakamla birebir \u00f6rt\u00fc\u015f\u00fcyor olmas\u0131.<\/span><\/p>\n

Ara\u015ft\u0131rmac\u0131lar h\u00e2l\u00e2 %10\u2019luk bir hata pay\u0131ndan s\u00f6z ediyor. Ancak kaydedilen renklerin dalgaboyunu daraltmak gibi \u00e7e\u015fitli y\u00f6ntemlerle yap\u0131lacak iyile\u015ftirmeler \u00f6l\u00e7\u00fcmleri k\u0131sa s\u00fcrede daha da keskinle\u015ftirecek. Sonu\u00e7ta daha \u015fimdiden, ula\u015ft\u0131\u011f\u0131 \u00e7\u00f6z\u00fcn\u00fcrl\u00fck ve keskinlik bak\u0131m\u0131ndan mevcut y\u00f6ntemleri geride b\u0131rakan bu yeni teknik, b\u00fcy\u00fckl\u00fck verilerinden yola \u00e7\u0131karak g\u00f6rd\u00fc\u011f\u00fcm\u00fcz y\u0131ld\u0131zlar\u0131n ne zaman do\u011fdu\u011funu, ne kadard\u0131r parlad\u0131\u011f\u0131n\u0131 ve muhtemel \u00f6l\u00fcm\u00fcn\u00fcn ne zaman olaca\u011f\u0131n\u0131 da s\u00f6yleyebilecek. K\u0131sacas\u0131 y\u0131ld\u0131z pop\u00fclasyonunun \u015feceresini \u00e7\u0131karmaya ve astronomi rehberlerinin ba\u015ftan yaz\u0131lmas\u0131na \u00e7ok az kald\u0131.<\/span><\/p>\n

Kaynak
\n<\/b>1) Tracey Bryant, \u201cSizing up a starry night\u201d, University of Delaware Daily, 15 Nisan 2019.
\n<\/span>2) \u201cAsteroids help scientists to measure the diameters of far away stars\u201d, Deutsches Elektronen-Synchrotron Desy News, 15 Nisan 2019.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

Gece g\u00f6ky\u00fcz\u00fcne bakt\u0131\u011f\u0131m\u0131zda g\u00f6rd\u00fc\u011f\u00fcm\u00fcz y\u0131ld\u0131zlar hakk\u0131nda pek \u00e7ok \u015fey s\u00f6yleyebiliriz: Konumlar\u0131, uzakl\u0131klar\u0131, hatta s\u0131cakl\u0131klar\u0131\u2026 Ancak aradaki mesafeden dolay\u0131 boyutlar\u0131n\u0131 tam olarak bilmek m\u00fcmk\u00fcn de\u011fil diye d\u00fc\u015f\u00fcn\u00fcr\u00fcz. Oysa g\u00f6r\u00fcnen o ki, m\u00fcmk\u00fcn olmayan, cevab\u0131 olan sorular\u0131n g\u00fcn\u00fcn birinde yan\u0131t bulmamas\u0131ym\u0131\u015f. Zira Nature Astronomy dergisinin 15 Nisan say\u0131s\u0131nda yay\u0131mlanan, 23 \u00fcniversiteden uluslararas\u0131 bir ekibin \u00e7e\u015fitli evrelerine dahil […]<\/p>\n","protected":false},"author":184,"featured_media":33875,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[30,19],"tags":[4793,4794,4791,4792],"class_list":["post-33876","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-astronomi","category-bilim-gundemi","tag-difraksiyon","tag-okultasyon","tag-veritas-teleskoplari","tag-yildizlarin-capi"],"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