{"id":15732,"date":"2016-05-01T16:13:40","date_gmt":"2016-05-01T13:13:40","guid":{"rendered":"http:\/\/109.232.216.219\/~bilimvegelecek\/?p=15732"},"modified":"2018-01-03T16:37:35","modified_gmt":"2018-01-03T13:37:35","slug":"dikkat-dikkat-gravitasyonel-dalgalar","status":"publish","type":"post","link":"https:\/\/bilimvegelecek.com.tr\/index.php\/2016\/05\/01\/dikkat-dikkat-gravitasyonel-dalgalar","title":{"rendered":"Dikkat! Dikkat! Gravitasyonel dalgalar\u2026"},"content":{"rendered":"

2002-2010<\/em>: LIGO\u2019nun ilk \u00e7al\u0131\u015fmalar\u0131 ba\u015flad\u0131 – gravitasyonel dalgalar alg\u0131lanmad\u0131. 2007: LIGO ve VIRGO ekipleri verileri payla\u015fma konusunda anla\u015ft\u0131lar; b\u00f6ylece, gravitasyonel dalga alga\u00e7lar\u0131 global a\u011f\u0131 olu\u015fturuldu. 2010-2015: LIGO alga\u00e7lar\u0131n\u0131n g\u00fcncellenmesi i\u00e7in 205 milyon dolar harcand\u0131. 2016: 11 \u015eubat\u2019ta NSF ve LIGO ekibi gravitasyonel dalgalar\u0131n ba\u015far\u0131l\u0131 bir bi\u00e7imde alg\u0131land\u0131\u011f\u0131n\u0131 duyurdu. <\/em><\/p>\n

\u201cDolays\u0131z olarak alg\u0131land\u0131\u011f\u0131nda, gravitasyonel dalgalar\u0131 Genel G\u00f6relili\u011fin s\u0131nanmas\u0131nda kullanabilecek miyiz? Hay\u0131r! \u00c7\u00fcnk\u00fc gravitasyonel dalga kayna\u011f\u0131 olabilecek cisimler (gravitasyonel \u00e7\u00f6kmeler, s\u00fcpernovalar\u0131n i\u00e7 b\u00f6lgeleri, kara delikler, k\u0131sa d\u00f6nemli \u00e7ift y\u0131ld\u0131z dizgeleri, \u00e7ift atarcalar, vb.) o denli karma\u015f\u0131kt\u0131r ki, bu cisimlerin yap\u0131 ve dinami\u011finin etkilerini Genel G\u00f6relilik etkilerinden ay\u0131rmak son derece zordur. Bu nedenle gravitasyonel dalgalar\u0131n alg\u0131lanmas\u0131 durumunda bile kullanaca\u011f\u0131m\u0131z y\u00f6ntem, Genel G\u00f6relili\u011fi do\u011fru varsay\u0131p, kaynak cisimlerin yap\u0131 ve dinami\u011fine ili\u015fkin bilgilenmeyi s\u00fcrd\u00fcrmek olacakt\u0131r.<\/p>\n

\u201cGravitasyonel dalgalar\u0131n dolays\u0131z alg\u0131lanmas\u0131 ger\u00e7ekle\u015fti\u011finde g\u00f6kbilimin yeni bir ara\u015ft\u0131rma dal\u0131, Gravitasyonel Dalga G\u00f6kbilimi<\/strong> ba\u015flayacak. Optik, radyo, X-\u0131\u015f\u0131nlar\u0131, mor\u00f6te ve k\u0131z\u0131l\u00f6te dalgaboylar\u0131nda \u00e7al\u0131\u015fan g\u00f6kbilimciler nas\u0131l ki Maxwell\u2019in elektromanyetik kuram\u0131n\u0131 s\u0131namak yerine, kayna\u011fa ili\u015fkin bilgilenmeyi ye\u011fliyorsa, gravitasyonel dalga g\u00f6kbilimcisi de bu dalgalar\u0131 inceleyerek evrenin yap\u0131s\u0131na ili\u015fkin bilgilenmeye y\u00f6nelecektir.\u201d (Will, C. M., Was Einstein Right<\/em>, Basic Books, 1986)<\/p>\n

\u00d6ng\u00f6r\u00fcden ger\u00e7e\u011fe giden yol: Gravitasyonel dalgalar\u0131n ara\u015ft\u0131r\u0131lma tarihi<\/strong><\/p>\n

1915: Albert Einstein Genel G\u00f6relilik kuram\u0131n\u0131 yay\u0131mlat\u0131r; Einstein graviteyi<\/em> uzay zaman s\u00fcredurumunun k\u00fctle veya erkeyle b\u00fck\u00fclmesi olarak tan\u0131mlar.<\/p>\n

1916: Einstein belli y\u00f6r\u00fcngelerde d\u00f6nen b\u00fcy\u00fck k\u00fctleli g\u00f6k cisimlerinin uzay zaman s\u00fcredurumunda gravitasyonel dalga ad\u0131 verilen b\u00fck\u00fclmelere neden olaca\u011f\u0131n\u0131 \u00f6ng\u00f6r\u00fcr.<\/p>\n

1936: Einstein\u2019\u0131n makalesini inceleyen hakem makaledeki bir yanl\u0131\u015fa i\u015faret edince Einstein tekrar d\u00fc\u015f\u00fcn\u00fcr ve bas\u0131ma g\u00f6nderdi\u011fi metinde dalgalar\u0131n var olmad\u0131\u011f\u0131n\u0131 ileri s\u00fcrer.<\/p>\n

1962: Rus fizik\u00e7ileri M. E. Gertsenshtein ve V. I. Pustovoit kimsenin dikkatini \u00e7ekmeyen bir makale yay\u0131mlat\u0131rlar ve makalede gravitasyonel dalgalar\u0131n optik bir y\u00f6ntemle alg\u0131lanmas\u0131na ili\u015fkin \u00e7izge (sketch) kullan\u0131rlar.<\/p>\n

1969: Fizik\u00e7i Joseph Weber b\u00fcy\u00fck k\u00fctleli bir al\u00fcminyum silindir kullanarak gravitasyonel dalgalar\u0131 alg\u0131lad\u0131\u011f\u0131n\u0131 savunur ancak yinelenen deneyler ba\u015far\u0131s\u0131zl\u0131kla sonu\u00e7lan\u0131r.<\/p>\n

1972: Cambridge MIT (Massachusetts Institute of Technology) profes\u00f6rlerinden Rainer Weiss gravitasyonel dalgalar\u0131n optik y\u00f6ntemle alg\u0131lanabilece\u011fini ba\u011f\u0131ms\u0131z olarak ileri s\u00fcrer.<\/p>\n

1974: \u00c7ift atarcalar\u0131n dolanma d\u00f6nemlerinin azalmas\u0131n\u0131 g\u00f6zlemleyen Joe Taylor ve Russell Hulse adl\u0131 g\u00f6kbilimciler d\u00f6nem azalmas\u0131n\u0131 n\u00f6tron y\u0131ld\u0131z\u0131n gravitasyonel dalgalar yoluyla erke yitirmesi \u015feklinde yorumlad\u0131lar ve bu \u00e7al\u0131\u015fmalar\u0131 nedeniyle Nobel \u00f6d\u00fcl\u00fc ald\u0131lar.<\/p>\n

1979: Ulusal Bilim Vakf\u0131 (NSF – National Science Foundation) LIGO tasar\u0131m\u0131n\u0131n geli\u015ftirilmesi i\u00e7in Pasadena\u2019daki Kaliforniya Teknoloji Enstit\u00fcs\u00fcn\u00fc ve Massachusetts Teknoloji Enstit\u00fcs\u00fcn\u00fc parasal olarak destekledi.<\/p>\n

1990: Ulusal Bilim Vakf\u0131 LIGO deneyine 250 milyon dolar vermeyi onad\u0131.<\/p>\n

1992: LIGO sitesi i\u00e7in Washington ve Louisiana\u2019da yer belirleme \u00e7al\u0131\u015fmalar\u0131 tamamland\u0131; 2 y\u0131l sonra yap\u0131m\u0131na ba\u015fland\u0131.<\/p>\n

1995: LIGO ile birlikte gravitasyonel dalga alg\u0131layacak olan Almanya\u2019daki GEO600 gravitasyonel dalga algac\u0131n\u0131n yap\u0131m\u0131na ba\u015fland\u0131; 2002 y\u0131l\u0131nda GEO600 ile veri al\u0131nma s\u00fcreci ba\u015flad\u0131.<\/p>\n

1996: Italya\u2019daki VIRGO gravitasyonel dalga algac\u0131n\u0131n yap\u0131m\u0131na ba\u015fland\u0131;\u00a0 2007 y\u0131l\u0131nda veri al\u0131nma s\u00fcreci ba\u015flad\u0131.<\/p>\n

2002-2010: LIGO\u2019nun ilk \u00e7al\u0131\u015fmalar\u0131 ba\u015flad\u0131 – gravitasyonel dalgalar alg\u0131lanmad\u0131.<\/p>\n

2007: LIGO ve VIRGO ekipleri verileri payla\u015fma konusunda anla\u015ft\u0131lar; b\u00f6ylece, gravitasyonel dalga alga\u00e7lar\u0131 global a\u011f\u0131 olu\u015fturuldu<\/p>\n

2010-2015: LIGO alga\u00e7lar\u0131n\u0131n g\u00fcncellenmesi i\u00e7in 205 milyon dolar harcand\u0131.<\/p>\n

2015: Geli\u015fkin LIGO algac\u0131n\u0131n alg\u0131lama s\u00fcreci Eyl\u00fcl ay\u0131nda ba\u015flad\u0131.<\/p>\n

2016: 11 \u015eubat\u2019ta NSF ve LIGO ekibi gravitasyonel dalgalar\u0131n ba\u015far\u0131l\u0131 bir bi\u00e7imde alg\u0131land\u0131\u011f\u0131n\u0131 duyurdu.<\/p>\n

Elektromanyetik dalgalar ve giri\u015fim<\/strong><\/p>\n

LIGO alga\u00e7lar\u0131n\u0131n gravitasyonel dalgalar\u0131 alg\u0131lamada kulland\u0131\u011f\u0131 y\u00f6ntemi daha iyi anlayabilmek i\u00e7in elektromanyetik dalgalar\u0131n do\u011fas\u0131n\u0131 ve en az iki \u0131\u015f\u0131n\u0131m kayna\u011f\u0131ndan \u00e7\u0131kan ve kar\u015f\u0131la\u015fan elektromanyetik dalgalar\u0131 bekleyen yap\u0131c\u0131<\/strong> (constructive) ve y\u0131k\u0131c\u0131<\/strong> (destructive) giri\u015fimleri<\/strong> an\u0131msamada yarar var.<\/p>\n

\"\"Elektromanyetik dalgalar, ad\u0131 \u00fczerinde, elektrik alan ve manyetik alan\u0131n birlikteli\u011fidir (\u015eekil 1). Bu alanlar vekt\u00f6rel olarak simgelenir. Dalgan\u0131n yay\u0131ld\u0131\u011f\u0131 y\u00f6n elektrik ve manyetik alan\u0131n olu\u015fturdu\u011fu d\u00fczleme dik y\u00f6ndedir. Sin\u00fcsodial de\u011fi\u015fim g\u00f6steren elektrik ve manyetik alan vekt\u00f6rleri i\u00e7in tan\u0131mlanan bir \u00f6zellik de \u201cevre\u201ddir (phase). Evreler a\u00e7\u0131 dereceleriyle g\u00f6sterilir. \u015eekil 1\u2019de k\u0131rm\u0131z\u0131<\/u> renkle g\u00f6sterilen elektrik alan vekt\u00f6rlerini d\u00fc\u015f\u00fcnelim. \u015eeklin sol ba\u015f\u0131nda elektrik alan ve manyetik alan vekt\u00f6rleriyle dalgan\u0131n yay\u0131lma y\u00f6n vekt\u00f6r\u00fcn\u00fcn kesi\u015fti\u011fi nokta \u201cs\u0131f\u0131r evre\u201d (00<\/sup>)\u00a0 olarak adland\u0131r\u0131l\u0131r; sin\u00fcs e\u011frisinin maksimuma ula\u015ft\u0131\u011f\u0131 evre \u201c900<\/sup>\u201d; sonra tekrar s\u0131f\u0131rland\u0131\u011f\u0131 evre \u201c1800<\/sup>\u201d; elektrik alan vekt\u00f6rlerinin ters y\u00f6ne d\u00f6nd\u00fc\u011f\u00fc ve sin\u00fcs e\u011frisinin negatif y\u00f6nde maksimum oldu\u011fu evre \u201c2700<\/sup>\u201d, vd.<\/p>\n

\u015eekil 2 \u201c\u00fcst\u201dte iki farkl\u0131 kaynaktan \u00e7\u0131kan elektromanyetik dalgalar\u0131n birbiriyle ayn\u0131 evrede (in phase) kar\u015f\u0131la\u015ft\u0131\u011f\u0131 g\u00f6steriliyor. K\u0131sacas\u0131, dalgalar\u0131n 00<\/sup>, 900<\/sup>, 1800<\/sup>, 2700<\/sup>, vd. evreleri \u00e7ak\u0131\u015f\u0131k. Bu durumda dalgalar yap\u0131c\u0131 giri\u015fimde<\/strong> (constructive interference) bulunur. Yap\u0131c\u0131 giri\u015fimle ortaya \u00e7\u0131kan dalgan\u0131n genli\u011fi artar. \u015eekil 2 \u201calt\u201d yine iki farkl\u0131 kaynaktan \u00e7\u0131kan elektromanyetik dalgalar\u0131n 1800<\/sup>lik evre fark\u0131yla kar\u015f\u0131la\u015ft\u0131\u011f\u0131 g\u00f6steriliyor. Bu dalgalar\u0131n pozitif y\u00f6ndeki elektrik alan vekt\u00f6r\u00fcyle ayn\u0131 noktada ayn\u0131 uzunlukta ve z\u0131t y\u00f6ndeki elektrik alan vekt\u00f6rleri birbirini s\u0131f\u0131rlad\u0131\u011f\u0131ndan y\u0131k\u0131c\u0131 giri\u015fim<\/strong> (destructive interference) olur ve elektromanyetik dalgalar s\u00f6ner.<\/p>\n

\"\"
\u015eekil 2. (\u00dcst) Ayn\u0131 evrede kar\u015f\u0131la\u015fan iki elektromanyetik dalga yap\u0131c\u0131 giri\u015fimde bulunur ve toplam dalgan\u0131n genli\u011fi artar. (Alt) 1800 lik evre fark\u0131yla kar\u015f\u0131la\u015fan iki elektromanyetik dalga y\u0131k\u0131c\u0131 giri\u015fimde bulunur ve sinyal ortadan kalkar. Sa\u011fdaki \u015fekilde silindirik ayg\u0131t lazer kayna\u011f\u0131d\u0131r. LIGO\u2019da kaynaktan \u00e7\u0131kan lazer \u0131\u015f\u0131n demetini 4 km\u2019lik yolculu\u011fa \u00e7\u0131karan bir demet yar\u0131c\u0131 (beam splitter) vard\u0131r. \u015eeklin \u00fcst taraflar\u0131nda \u00e7emberlerle g\u00f6sterilen aynalardan yans\u0131yan lazer \u0131\u015f\u0131nlar geriye demet yar\u0131c\u0131ya ve oradan da \u015feklin sa\u011f alt\u0131ndaki e\u015fkenar d\u00f6rtgen g\u00f6r\u00fcn\u00fcm\u00fcndeki algaca gelir.<\/figcaption><\/figure>\n

Gravitasyonel dalgalar\u0131n yoklu\u011funda alga\u00e7lar aras\u0131ndaki uzakl\u0131k e\u015fit olarak kal\u0131r, \u0131\u015f\u0131k dalgalar\u0131 birbirini y\u0131k\u0131c\u0131 giri\u015fimle<\/strong> yok eder, alga\u00e7ta sinyal olu\u015fmaz. E\u011fer gravitasyonel dalgalar alga\u00e7lardan ge\u00e7erse, uzay zaman s\u00fcredurumunu bir y\u00f6nde gererken di\u011fer y\u00f6nde b\u00fczer (bkz. \u015eekil 3).<\/p>\n

\"\"Sayfa d\u00fczleminde dik do\u011frultuda yay\u0131lan gravitasyonel dalgan\u0131n \u2018uzama\u2019\/ \u2018k\u0131salma\u2019 genli\u011fi \u201ch\u201d ile betimlenir. Gravitasyonel dalga \u00e7ember \u00fczerine da\u011f\u0131lm\u0131\u015f olan test par\u00e7ac\u0131klar\u0131n\u0131 elips \u015fekline d\u00f6n\u00fc\u015ft\u00fcr\u00fcr. Dalgan\u0131n yar\u0131m \u00e7evrimi boyunca elipsin b\u00fcy\u00fck ekseni, \u00f6rne\u011fin x-y\u00f6n\u00fcndeyse, di\u011fer yar\u0131m \u00e7evrim boyunca y-eksenine d\u00f6ner. Titre\u015fimsel olan bu bozulma, y\u00f6nelimi \u015fekildeki gibi olan Michelson giri\u015fim\u00f6l\u00e7eriyle \u00f6l\u00e7\u00fclebilir. Uzunluktaki titre\u015fimler LIGO\u2019nun her iki kolundan gelen lazer \u0131\u015f\u0131\u011f\u0131n\u0131n evre kaymalar\u0131n\u0131 de\u011fi\u015ftirir. Lazer \u0131\u015f\u0131\u011f\u0131ndaki bu evre kaymalar\u0131 da ye\u015fil renkli yar\u0131m \u00e7ember ile g\u00f6sterilen foto alga\u00e7 taraf\u0131ndan alg\u0131lan\u0131r. \u015eekil 3, gravitasyonel dalgan\u0131n do\u011frusal u\u00e7la\u015fm\u0131\u015f bi\u00e7emlerinden birini g\u00f6steriyor.<\/p>\n

\"\"
\u015eekil 4. \u00c7ift kara deliklerin birle\u015ferek bir tek kara deli\u011fe d\u00f6n\u00fc\u015ft\u00fc\u011f\u00fcne i\u015faret eden sinyal (LIGO Laboratuvar\u0131 \/ NSF) (http:\/\/www.symmetrymagazine.org\/article\/ligo-sees-gravitational-waves).<\/figcaption><\/figure>\n

Bu durumda giri\u015fim\u00f6l\u00e7erin bir kolu di\u011ferinden daha uzun olur \u0131\u015f\u0131k dalgalar\u0131 gerekti\u011fi gibi z\u0131t evrelerde bulu\u015farak y\u0131k\u0131c\u0131 giri\u015fim<\/strong> yapamaz ve gravitasyonel dalgalar\u0131n varl\u0131\u011f\u0131na i\u015faret eden sinyal alg\u0131lanm\u0131\u015f olur (\u015eekil 4). LIGO \u00e7ok duyarl\u0131d\u0131r, aynalar aras\u0131ndaki uzakl\u0131k de\u011fi\u015fimi protonun \u00e7ap\u0131n\u0131n binde biri denli k\u00fc\u00e7\u00fck de olsa alg\u0131lar.<\/p>\n

\u00c7arp\u0131\u015fan iki kara delikten gelen ses<\/strong><\/p>\n

https:\/\/www.ligo.caltech.edu\/video\/ligo20160211v2 uzant\u0131s\u0131ndaki videoda i\u015fitilen ses, \u00e7arp\u0131\u015fan kara deliklerin sald\u0131\u011f\u0131 gravitasyonel dalgalar\u0131n ses dalgalar\u0131na d\u00f6n\u00fc\u015ft\u00fcr\u00fclmesiyle \u00fcretilmi\u015ftir. 14 Eyl\u00fcl 2015 tarihinde LIGO, her biri G\u00fcne\u015f k\u00fctlesinin yakla\u015f\u0131k 30 kat\u0131 olan iki karadeli\u011fin birle\u015fmesi sonucu \u00fcretilen gravitasyonel dalgalar\u0131 g\u00f6zlemi\u015ftir. Saniyenin fraksiyonlar\u0131 denli k\u0131sa s\u00fcren bu son derece g\u00fc\u00e7l\u00fc \u00e7arp\u0131\u015fma g\u00f6zlenebilir evrenimizdeki t\u00fcm y\u0131ld\u0131zlar\u0131n sald\u0131\u011f\u0131 erkeden 50 kez daha b\u00fcy\u00fck erke a\u00e7\u0131\u011fa \u00e7\u0131karm\u0131\u015ft\u0131r.<\/p>\n

Animasyonun ilk iki a\u015famas\u0131nda ses dalgalar\u0131n\u0131n frekans\u0131yla gravitasyonel dalgalar\u0131n frekans\u0131 birbiriyle tam uyu\u015fum i\u00e7inde; ikinci iki a\u015famal\u0131 animasyondaysa frekans aral\u0131\u011f\u0131 insanlar\u0131n sesleri i\u015fitme frekans\u0131na uygun olarak y\u00fckseltilmi\u015ftir. Animasyon, orijinal frekanslarda iki kez daha g\u00f6sterilmi\u015ftir.<\/p>\n

Kara delikler birbirine do\u011fru sarmal y\u00f6r\u00fcngelerde giderek yakla\u015ft\u0131k\u00e7a gravitasyonel dalgalar\u0131n frekans\u0131 da artar. Bu seslere biliminsanlar\u0131 \u201cc\u0131v\u0131lt\u0131\u201d diyor, \u00e7\u00fcnk\u00fc gravitasyonel dalga \u00fcreten baz\u0131 olaylar ku\u015flar\u0131n c\u0131v\u0131lt\u0131s\u0131na benzer sesler \u00e7\u0131kar\u0131r.<\/p>\n

Not:<\/strong> \u0130nsanlar (Ludwig Bethooven hari\u00e7!) 20 Hz – 20 kHz frekans aral\u0131\u011f\u0131ndaki sesleri alg\u0131lar.<\/p>\n

Genel G\u00f6relilik kuram\u0131na g\u00f6re, birbiri \u00e7evresinde y\u00f6r\u00fcngede dolanan iki kara delik gravitasyonel dalga \u00fcreterek erke yitirir ve milyarlarca y\u0131l s\u00fcren d\u00f6nemde birbirine giderek yakla\u015f\u0131r ve son dakikada \u00e7ok h\u0131zl\u0131 bir s\u00fcre\u00e7le \u00e7arp\u0131\u015f\u0131rlar. \u00c7arp\u0131\u015fma hemen hemen \u0131\u015f\u0131k h\u0131z\u0131n\u0131n yar\u0131s\u0131na denk bir h\u0131zla olur, sonu\u00e7ta bir tek kara deli\u011fe d\u00f6n\u00fc\u015f\u00fcrler, k\u00fctlelerinin toplam\u0131n\u0131n bir k\u0131sm\u0131 Einstein\u2019\u0131n \u00fcnl\u00fc form\u00fcl\u00fc E = mc2<\/sup> ye g\u00f6re erkeye d\u00f6n\u00fc\u015f\u00fcr (Einstein\u2019\u0131n E = mc2<\/sup> form\u00fcl\u00fcn\u00fc nas\u0131l ke\u015ffetti\u011fi a\u015fa\u011f\u0131daki \u015fekilde g\u00f6steriliyor!). Bu erke, gravitasyonel dalgan\u0131n son g\u00fc\u00e7l\u00fc dalgas\u0131 olarak sal\u0131n\u0131r. LIGO i\u015fte bu son a\u015famada \u00fcretilen gravitasyonel dalgalar\u0131n\u0131 alg\u0131lam\u0131\u015ft\u0131r.<\/p>\n

\"\"
Einstein E = mc2 ye giden yolda ilerliyor!<\/figcaption><\/figure>\n

Gravitasyonel dalgalar\u0131n varl\u0131\u011f\u0131 ilk kez 1970\u2019li ve 1980\u2019li y\u0131llarda Joseph Taylor, Jr. ve \u00e7al\u0131\u015fma arkada\u015flar\u0131nca g\u00f6sterilmi\u015ftir. Taylor ve Russell Hulse 1974 y\u0131l\u0131nda bir \u00e7ift atarca dizgesinin varl\u0131\u011f\u0131n\u0131 bulmu\u015flard\u0131r. Taylor ve Joel M. Weisberg 1982 y\u0131l\u0131nda bir \u00e7ift y\u0131ld\u0131z dizgesindeki atarcan\u0131n y\u00f6r\u00fcnge d\u00f6neminin azald\u0131\u011f\u0131n\u0131 bulmu\u015flar ve bu azalman\u0131n nedeninin atarca taraf\u0131ndan sal\u0131nan gravitasyonel dalga erkesi oldu\u011funu ileri s\u00fcrm\u00fc\u015flerdir. \u00c7ift Atarcalar\u0131n ke\u015ffi ve bu ke\u015ffin gravitasyonel dalga \u00f6l\u00e7\u00fcmleri i\u00e7in kullan\u0131labilece\u011fi olas\u0131l\u0131\u011f\u0131 nedeniyle Hulse ve Taylor 1993 y\u0131l\u0131nda Fizik dal\u0131nda Nobel \u00d6d\u00fcl\u00fc kazanm\u0131\u015flard\u0131r.<\/p>\n

LIGO alga\u00e7lar\u0131n\u0131n bulgusu gravitasyonel dalgalara ili\u015fkin ilk g\u00f6zlemdir. Bu bulgu, Yer yak\u0131n\u0131ndan ge\u00e7en gravitasyonel dalgalar\u0131n uzay-zaman s\u00fcredurumunda ortaya \u00e7\u0131kard\u0131klar\u0131 k\u00fc\u00e7\u00fck b\u00fck\u00fclmenin \u00f6l\u00e7\u00fcm\u00fcyle yap\u0131lm\u0131\u015ft\u0131r.<\/p>\n

LIGO ara\u015ft\u0131rmas\u0131, ABD\u2019deki \u00fcniversitelerden ve di\u011fer 14 \u00fclkeden kat\u0131lan 1000\u2019den fazla biliminsan\u0131 taraf\u0131ndan olu\u015fturulan LIGO Bilimsel \u0130\u015fbirli\u011fi (LSC – LIGO Scientific Collaboration) ile y\u00fcr\u00fct\u00fclm\u00fc\u015ft\u00fcr. LSC\u2019deki 90\u2019dan fazla \u00fcniversite ve ara\u015ft\u0131rma enstit\u00fcs\u00fc alga\u00e7 teknolojisi geli\u015ftirmi\u015f ve veri \u00e7\u00f6z\u00fcmlemesi yapm\u0131\u015ft\u0131r. LSC\u2019de yakla\u015f\u0131k 250 \u00f6\u011frenci de i\u015fbirli\u011fine b\u00fcy\u00fck katk\u0131da bulunmu\u015ftur. LSC alga\u00e7 a\u011f\u0131 LIGO giri\u015fim\u00f6l\u00e7erleri ve GEO600 algac\u0131ndan olu\u015fuyor. GEO tak\u0131m\u0131nda Max Planck Enstit\u00fcs\u00fc Gravitasyonel Fizik b\u00f6l\u00fcm\u00fcnde (Albert Einstein Institute, AEI) Hannover Leibniz \u00dcniversitesi\u2019nde, Glasgow \u00dcniversitesi\u2019nde, Cardiff \u00dcniversitesi\u2019nde, Birmingham \u00dcniversitesi\u2019nde ve \u0130ngiltere\u2019deki di\u011fer \u00fcniversitelerde ve \u0130spanya Balearic Adalar\u0131 \u00dcniversitesi\u2019nde \u00e7al\u0131\u015fanlar yer alm\u0131\u015ft\u0131r.<\/p>\n

Ku\u015fkucular\u0131n ku\u015fkular\u0131n\u0131 gidermek gerek!<\/strong><\/p>\n

LIGO fizik\u00e7ileri be\u015f ay boyunca bulgular\u0131n\u0131 s\u0131k\u0131 bir denetim alt\u0131na ald\u0131lar. Ara\u015ft\u0131r\u0131c\u0131lar\u0131n \u00e7o\u011fu alg\u0131lanan sinyalin gravitasyonel dalgalardan gelen ger\u00e7ek bir sinyal olup olmad\u0131\u011f\u0131n\u0131 bilemez. LIGO genellikle alg\u0131lad\u0131\u011f\u0131 sinyallere \u201cblind injections\u201d denen, ayg\u0131tlar\u0131 s\u0131nayan ve ara\u015ft\u0131rmac\u0131lar\u0131 da uyan\u0131k tutma amac\u0131yla sahte sinyalleri de ekler. Ancak 14 Eyl\u00fcl 2015 tarihinde \u201cblind injection\u201d dizgesi \u00e7al\u0131\u015fm\u0131yordu. Fizik\u00e7iler 5 y\u0131l s\u00fcren ve 205 milyon dolara malolan g\u00fcncellenmi\u015f ve duyarl\u0131l\u0131\u011f\u0131 art\u0131r\u0131lm\u0131\u015f olan ayg\u0131t\u0131n yap\u0131m\u0131n\u0131 tamamlam\u0131\u015flard\u0131. \u0130\u015fbirli\u011fi i\u00e7inde \u00e7al\u0131\u015fan t\u00fcm ara\u015ft\u0131rmac\u0131lar sinyalin b\u00fcy\u00fck bir olas\u0131l\u0131kla ger\u00e7ek oldu\u011funda g\u00f6r\u00fc\u015f birli\u011findeydi. Gonzales, \u201cO g\u00fcn sinyalin do\u011fru oldu\u011funa kanaat getirdim\u201d dedi.<\/p>\n

\"\"
Sol: \u201cOh, evet\u2026\u00c7arp\u0131\u015fan kara deliklerden gelen ses\u2026sesler hala yineleniyor.\u201d;
Sa\u011f: \u201cBirinci \u00e7\u0131k\u0131nt\u0131 kara deliklerin \u00e7arp\u0131\u015fmas\u0131ndan, ikincisi de kutlama yapan bilim insanlar\u0131ndan gelen ses\u201d.<\/figcaption><\/figure>\n

Buna kar\u015f\u0131n LIGO fizik\u00e7ileri, sinyalin k\u00f6t\u00fc ama\u00e7l\u0131 bir \u015faka olabilece\u011fi olas\u0131l\u0131\u011f\u0131n\u0131 da dikkate alarak t\u00fcm sahte se\u00e7enekleri ay\u0131klamal\u0131yd\u0131lar. Reitze, \u201cSinyalin bir muzip taraf\u0131ndan \u015faka olarak \u00fcretilmi\u015f olup olmad\u0131\u011f\u0131n\u0131 bir ay boyunca ara\u015ft\u0131rd\u0131k\u201d dedi. Gonzales, \u201cBu gravitasyonel dalgalar\u0131n ilk alg\u0131lan\u0131\u015f\u0131yd\u0131, o nedenle yan\u0131lg\u0131ya yer b\u0131rakmamal\u0131yd\u0131k\u201d dedi.<\/p>\n

Glasgow \u00dcniversitesi fizik ve astronomi profes\u00f6r\u00fc Sheila Rowan, \u201cBilimin bu \u00e7ok \u00f6nemli d\u00f6n\u00fcm noktas\u0131 t\u00fcm d\u00fcnyadaki biliminsanlar\u0131n\u0131n ortak \u00e7al\u0131\u015fmas\u0131yla olas\u0131 k\u0131l\u0131nm\u0131\u015ft\u0131r. GEO600 algac\u0131m\u0131z i\u00e7in geli\u015ftirilmi\u015f olan lazer ve s\u00fcspansiyon teknolojisi, geli\u015fkin LIGO\u2019yu, bug\u00fcne dek geli\u015ftirilmi\u015f olan gravitasyonel dalga alga\u00e7lar\u0131 i\u00e7inde en duyarl\u0131 d\u00fczeye \u00e7\u0131karm\u0131\u015ft\u0131r\u201d dedi.<\/p>\n

Gravitasyonel dalgalara neden olan olay\u0131n y\u00f6n\u00fcn\u00fc do\u011fru olarak saptayabilmek ve sinyalin yerel olaylardan de\u011fil de g\u00f6ky\u00fcz\u00fcnden kaynakland\u0131\u011f\u0131n\u0131 saptayabilmek i\u00e7in ba\u011f\u0131ms\u0131z ve birbirinden olabildi\u011fince ayr\u0131 noktalara konu\u015flanm\u0131\u015f g\u00f6zlemevlerine gereksinim vard\u0131r.<\/p>\n

Bu ama\u00e7la, \u00fc\u00e7\u00fcnc\u00fc geli\u015fkin LIGO algac\u0131n\u0131n Hindistan yar\u0131madas\u0131nda konu\u015flanmas\u0131 i\u00e7in LIGO laboratuar\u0131 Hindistan\u2019daki biliminsanlar\u0131yla s\u0131k\u0131 bir i\u015fbirli\u011fi i\u00e7inde \u00e7al\u0131\u015f\u0131yor. \u00c7al\u0131\u015fmada yer alan kurumlar \u015funlard\u0131r: Inter-University Centre for Astronomy and Astrophysics, the Raja Ramanna Centre for Advanced Technology ve Institute for Plasma. Hindistan h\u00fck\u00fcmetinin onay\u0131n\u0131 bekleyen proje, gelecek on y\u0131l i\u00e7inde g\u00f6zlemlere ba\u015flayabilir. Ama\u00e7lanan bu ek alga\u00e7, gravitasyonel dalga kaynaklar\u0131n\u0131n konumunu saptayacak olan global alga\u00e7 a\u011f\u0131n\u0131n yetene\u011fini art\u0131racakt\u0131r.<\/p>\n

Avustralya Ulusal \u00dcniversitesi Gravitasyonel Fizik Merkezi y\u00f6neticisi ve fizik profes\u00f6r\u00fc David McClelland, \u201c\u00dcmit ediyoruz ki, gravitasyonel dalgalara ili\u015fkin bu ilk alg\u0131lama global alga\u00e7lar a\u011f\u0131n\u0131n yap\u0131m\u0131n\u0131 h\u0131zland\u0131racak ve \u00e7ok iletiler sunan g\u00f6kbilim \u00e7a\u011f\u0131nda kayna\u011f\u0131n konumunun \u00e7ok sa\u011fl\u0131kl\u0131 olarak saptanmas\u0131na yard\u0131mc\u0131 olacakt\u0131r.\u201d (https:\/\/www.ligo.caltech.edu\/news\/ligo20160211)<\/p>\n

G\u00fcr\u00fclt\u00fc kaynaklar\u0131n\u0131n tan\u0131s\u0131<\/strong><\/p>\n

B.P. Abbott, R. Abbott, T.D. Abbott ve arkada\u015flar\u0131n\u0131n, \u201cCharacterization of transient noise in Advanced LIGO relevant to gravitational wave signalGW150914<\/em>\u201d ba\u015fl\u0131kl\u0131 makalesinde de\u011fi\u015fik kaynaklar\u0131n \u00fcretti\u011fi g\u00fcr\u00fclt\u00fclerin tan\u0131lar\u0131n\u0131n yap\u0131ld\u0131\u011f\u0131 anlat\u0131l\u0131yor: (arXiv:1602.03844v2 [gr-qc] 16 Feb 2016)<\/p>\n

G\u00fcr\u00fclt\u00fc Kaynaklar\u0131n\u0131n Tan\u0131s\u0131n\u0131n Yap\u0131lmas\u0131<\/strong><\/p>\n

LIGO alga\u00e7lar\u0131n\u0131n her biri 200.000 adet yard\u0131mc\u0131 kanal (auxiliary channels) yard\u0131m\u0131yla algac\u0131n davran\u0131\u015f\u0131n\u0131 ve \u00e7evre ko\u015fullar\u0131n\u0131 denetler. Bu kanallar, gravitasyonel dalgalarla e\u015fle\u015febilecek gizilg\u00fcce (potansiyele) sahip s\u00fcre\u00e7leri g\u00f6zler; s\u00f6z\u00fc edilen kanallar ayg\u0131tlardaki yan\u0131lg\u0131lar\u0131n ve g\u00fcr\u00fclt\u00fc korelasyonlar\u0131n\u0131n tan\u0131s\u0131n\u0131 yaparlar.<\/p>\n

Algac\u0131n g\u00fcr\u00fclt\u00fc tan\u0131s\u0131 yapan kanallar\u0131na \u00f6rnek olarak optik ayg\u0131tlar\u0131n a\u00e7\u0131sal kaymalar\u0131n\u0131n \u00f6l\u00e7\u00fcm\u00fc; titre\u015fim odas\u0131n\u0131n optik ayg\u0131t\u0131n\u0131n denetimini yapan sinyaller; bir aynadan ge\u00e7irilen ve bir dizi diod taraf\u0131ndan alg\u0131lanan \u0131\u015f\u0131k say\u0131labilir. Gravitasyonel dalga adaylar\u0131n\u0131n tan\u0131s\u0131n\u0131n yap\u0131lmas\u0131na ek olarak ardalandan kaynaklanan ve yard\u0131mc\u0131 kanallar i\u00e7inde gravitasyonel dalgalarla e\u015f zamanl\u0131 olu\u015fabilecek g\u00fcr\u00fclt\u00fcler \u00fczerinde saatler veya g\u00fcnler s\u00fcren \u00e7al\u0131\u015fmalar da yap\u0131lmaktad\u0131r.<\/p>\n

Astrofiziksel kaynaklar\u0131n, milisaniye ile birka\u00e7 saniye aral\u0131\u011f\u0131nda s\u00fcren ge\u00e7ici sinyallerinin tan\u0131s\u0131 da yap\u0131labiliyor.<\/p>\n

A\u015fa\u011f\u0131da sunulan baz\u0131 g\u00fcr\u00fclt\u00fcler, gravitasyonel dalgalar\u0131n ara\u015ft\u0131r\u0131ld\u0131\u011f\u0131 ardalana \u00f6nemli \u00f6l\u00e7\u00fcde etki yapar.<\/p>\n

– Baz\u0131 insan-t\u00fcr\u00fcmsel (antropojenik) g\u00fcr\u00fclt\u00fc kaynaklar\u0131 gravitasyonel dalgalar \u00fczerinde k\u0131sa s\u00fcreli ge\u00e7ici etki yapabilir. \u00d6rne\u011fin, vakum h\u00fccresinin bulundu\u011fu odalardan birindeki insan etkinlikleri veya yak\u0131n b\u00f6lgedeki in\u015faat alanlar\u0131ndan gelen kesikli ancak ye\u011fin yer kazma i\u015flemleri. B\u00f6ylesi titre\u015fimsel veya akustik g\u00fcr\u00fclt\u00fcleri azaltmak amac\u0131yla, alga\u00e7lar\u0131n veri toplad\u0131\u011f\u0131 s\u0131ralarda alga\u00e7tan sorumlu personel, alga\u00e7lar\u0131n optik ayg\u0131tlar\u0131n\u0131n bulundu\u011fu odalara giri\u015f \u00e7\u0131k\u0131\u015f yapmazlar. Algac\u0131 etkileyecek olan herhangi bir antropojenik g\u00fcr\u00fclt\u00fc bir dizi ivmelendirici (accelerometers), sismometre ve mikrofon ile denetlenir.<\/p>\n

– Depremler de alga\u00e7larda frekanslar\u0131 0,03 – 0,1 Hz aral\u0131\u011f\u0131nda, e\u011fer deprem merkezi yak\u0131nlardaysa daha y\u00fcksek frekanslarda yer sars\u0131nt\u0131lar\u0131 \u00fcretir. Depremin neden oldu\u011fu sismik dalgalar\u0131n en b\u00fcy\u00fck genli\u011fe sahip olan R-dalgalar\u0131 gravitasyonel dalga verilerinin niteli\u011fini \u00e7ok k\u00f6t\u00fc bir bi\u00e7imde etkiler. Bu t\u00fcr dalgalar alga\u00e7lar\u0131n i\u015flememesine veya optik ayg\u0131tlarda d\u00fc\u015f\u00fck frekansl\u0131 devinimlere, lazer \u0131\u015f\u0131\u011f\u0131n\u0131n sa\u00e7\u0131lmas\u0131na neden olur. LIGO alga\u00e7lar\u0131na yerle\u015ftirilmi\u015f olan sismometreler depremlerin neden oldu\u011fu tedirginliklerin tan\u0131s\u0131n\u0131 kolayca yapar.<\/p>\n

– Radyo frekans (RF) mod\u00fclasyon bandlar\u0131 alga\u00e7lar i\u00e7indeki de\u011fi\u015fik optik odalar\u0131 (cavities) denetler. Lazer girdi alan\u0131na 9 ve 45 MHz\u2019de iki mod\u00fclasyon uygulan\u0131r. LIGO-Hanford\u2019da \u00e7\u00f6z\u00fcmlemelerin ba\u015flad\u0131\u011f\u0131 d\u00f6nemden beri 45 MHz\u2019de i\u015flem yapan elektro-optik mod\u00fclat\u00f6r dizgesinde zaman zaman y\u00fcksek oranda g\u00fcr\u00fclt\u00fc alg\u0131lanm\u0131\u015ft\u0131r. Bu g\u00fcr\u00fclt\u00fc 10 Hz ve 2000 Hz kanallar\u0131 aras\u0131ndaki gravitasyonel dalga kanallar\u0131n\u0131 etkiler. Bu elektronik hatayla ilgili veri \u00e7\u00f6z\u00fcmlemelere kat\u0131lmam\u0131\u015ft\u0131r. \u0130lgili \u00e7al\u0131\u015fma GW150914 \u00e7\u00f6z\u00fcmlemesine uygulanm\u0131\u015ft\u0131r.<\/p>\n

\"\"
\u015eekil 5. Tiz sesli ge\u00e7ici g\u00fcr\u00fclt\u00fc (blip transient)<\/figcaption><\/figure>\n

Tiz sesli ge\u00e7ici (blip transients) g\u00fcr\u00fclt\u00fcler gravitasyonel dalga strain kanal\u0131nda (h(t)), zaman vs. frekans<\/strong> uzay\u0131nda \u201cg\u00f6zya\u015f\u0131 damlas\u0131\u201d bi\u00e7iminde, 30-250 Hz frekanslar\u0131nda ve sinyalin en y\u00fcksek g\u00fcc\u00fc d\u00fc\u015f\u00fck frekanslarda olmak \u00fczere g\u00f6r\u00fcl\u00fcr (bkz. \u015eekil 5).<\/p>\n

GW ile ili\u015fkili g\u00fcr\u00fclt\u00fc (Correlated noise)<\/strong><\/p>\n

Her iki algac\u0131 hemen hemen ayn\u0131 anda etkileyebilecek olan g\u00fcr\u00fclt\u00fc kaynaklar\u0131 gravitasyonel dalgalar\u0131 \u00f6yk\u00fcn\u00fcr (taklit eder – \u0130ng. imitate) ve bu g\u00fcr\u00fclt\u00fcler ardalan ara\u015ft\u0131rma de\u011ferlendirmelerinde zaman kayd\u0131rmas\u0131 yap\u0131larak ortaya \u00e7\u0131kar\u0131lamaz. Elektromanyetik g\u00fcr\u00fclt\u00fc kaynaklar\u0131 \u015fim\u015fek, G\u00fcne\u015f\u2019te s\u00fcregelen patlamal\u0131 s\u00fcre\u00e7ler ve G\u00fcne\u015f r\u00fczgar\u0131n\u0131n ve de radyo frekanslar\u0131nda (RF) yap\u0131lan ileti\u015fimlerin (communication) neden oldu\u011fu g\u00fcr\u00fclt\u00fclerdir. E\u011fer elektromanyetik g\u00fcr\u00fclt\u00fc h(t)\u2019yi etkileyecek denli g\u00fc\u00e7l\u00fcyse, radyo al\u0131c\u0131lar\u0131nda ve manyetometrelerde y\u00fcksek sinyal\/g\u00fcr\u00fclt\u00fc oran\u0131yla tan\u0131 kazanacakt\u0131r.<\/p>\n

\u015eim\u015fek \u00e7akmalar\u0131 t\u00fcm d\u00fcnyada (globally) saniyede onlarca kez olur. \u015eim\u015fekler manyetik Schumann rezonans\u0131n\u0131 uyart\u0131r. Bu rezonansta g\u00fcr\u00fclt\u00fc, temel frekans 8 Hz olmak \u00fczere hemen hemen harmonik dizi \u015feklinde g\u00f6r\u00fcl\u00fcr. Ancak, Schumann rezonans\u0131n\u0131n \u00fcretti\u011fi manyetik alan genlikleri pico<\/em> Tesla d\u00fczeyinde oldu\u011fu i\u00e7in h(t)\u2019de g\u00fc\u00e7l\u00fc sinyal \u00fcretemezler.<\/p>\n

LIGO yak\u0131nlar\u0131nda \u00e7akan bir \u015fim\u015fek (\u015fim\u015fek elektriksel ak\u0131md\u0131r) i\u015fitilebilir frekanslarda manyetik alan arac\u0131l\u0131\u011f\u0131yla h(t)\u2019de k\u0131sa s\u00fcreli bir g\u00fcr\u00fclt\u00fc uyart\u0131r. Ancak, \u00e7ok g\u00fc\u00e7l\u00fc \u015fim\u015fekler bile, her iki alga\u00e7ta bulunan fluxgate manyetometrelerde ayn\u0131 anda alg\u0131lanabilecek ye\u011finlikte manyetik alan \u00fcretemez.<\/p>\n

\u0130\u015fitilebilir frekans band\u0131ndaki elektromanyetik sinyaller insan ve g\u00fcne\u015f kaynakl\u0131 da olabilir. \u00d6rne\u011fin G\u00fcne\u015f radyo patlamalar\u0131 (flares) ve G\u00fcne\u015f r\u00fczgar\u0131yla ili\u015fkili elektrik y\u00fckl\u00fc par\u00e7ac\u0131klar. \u00c7\u00f6z\u00fcmleme d\u00f6neminde ger\u00e7ekle\u015fen g\u00fc\u00e7l\u00fc G\u00fcne\u015f ve jeomanyetik olaylar \u00fczerinde \u00e7al\u0131\u015f\u0131ld\u0131 ve alga\u00e7larda h(t) etkisi g\u00f6zlenmedi.<\/p>\n

\"\"
Gravitasyonel dalga g\u00f6zlemevleri<\/figcaption><\/figure>\n

Gravitasyonel dalga g\u00f6zlemevleri a\u011f\u0131<\/strong><\/p>\n

Gravitasyonel dalga alga\u00e7lar global a\u011f\u0131, biri Washington\/Hanford di\u011feri Louisiana\/Livingston\u2019da bulunan LIGO ikizleri ve Almanya\u2019daki GEO600. \u0130talya\u2019daki Virgo ve Japonya\u2019daki Kamioka Gravitasyonel Dalga Algac\u0131 (KAGRA) yenilenme a\u015famas\u0131nda olup i\u015flemlere 2016 (Virgo) ve 2018 y\u0131l\u0131nda (Kagra) ba\u015flamas\u0131 planlan\u0131yor. Alt\u0131nc\u0131 g\u00f6zlemevinin Hindistan\u2019da kurulmas\u0131 planlan\u0131yor. Gravitasyonel dalga g\u00f6zlemevlerinin t\u00fcm d\u00fcnyaya yay\u0131lmas\u0131 durumunda dalgalar\u0131n evrendeki konumu ve kayna\u011f\u0131 rahatl\u0131kla saptanabilecek.<\/p>\n","protected":false},"excerpt":{"rendered":"

2002-2010: LIGO\u2019nun ilk \u00e7al\u0131\u015fmalar\u0131 ba\u015flad\u0131 – gravitasyonel dalgalar alg\u0131lanmad\u0131. 2007: LIGO ve VIRGO ekipleri verileri payla\u015fma konusunda anla\u015ft\u0131lar; b\u00f6ylece, gravitasyonel dalga alga\u00e7lar\u0131 global a\u011f\u0131 olu\u015fturuldu. 2010-2015: LIGO alga\u00e7lar\u0131n\u0131n g\u00fcncellenmesi i\u00e7in 205 milyon dolar harcand\u0131. 2016: 11 \u015eubat\u2019ta NSF ve LIGO ekibi gravitasyonel dalgalar\u0131n ba\u015far\u0131l\u0131 bir bi\u00e7imde alg\u0131land\u0131\u011f\u0131n\u0131 duyurdu. \u201cDolays\u0131z olarak alg\u0131land\u0131\u011f\u0131nda, gravitasyonel dalgalar\u0131 Genel G\u00f6relili\u011fin […]<\/p>\n","protected":false},"author":475,"featured_media":15733,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[184,30,26],"tags":[277,1027,288,295,1833,1161],"class_list":["post-15732","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-147-sayi","category-astronomi","category-fizik","tag-einstein","tag-elektromanyetik-dalga","tag-fizik","tag-gorelilik","tag-gravitasyonel-dalga","tag-kutlecekim"],"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