{"id":34882,"date":"2019-06-25T05:11:27","date_gmt":"2019-06-25T02:11:27","guid":{"rendered":"https:\/\/bilimvegelecek.com.tr\/?p=34882"},"modified":"2019-06-25T06:25:11","modified_gmt":"2019-06-25T03:25:11","slug":"marsta-saptanan-metan-dunya-disi-yasam-umutlarini-yesertti","status":"publish","type":"post","link":"https:\/\/bilimvegelecek.com.tr\/index.php\/2019\/06\/25\/marsta-saptanan-metan-dunya-disi-yasam-umutlarini-yesertti","title":{"rendered":"Mars\u2019ta saptanan metan D\u00fcnya d\u0131\u015f\u0131 ya\u015fam umutlar\u0131n\u0131 ye\u015fertti"},"content":{"rendered":"

K\u00fcresel \u0131s\u0131nma yaratma potansiyeli CO<\/span>2<\/span>\u2019in 28 kat\u0131 olan metan gaz\u0131n\u0131 \u015fimdiye kadar iklim de\u011fi\u015fimi haberlerinden okuduk, bildik. Kendisi yery\u00fcz\u00fcn\u00fcn oksijenden yoksun kimi u\u00e7 noktalar\u0131nda, mesela Alaska\u2019n\u0131n buz ve toprak kar\u0131\u015f\u0131m\u0131 y\u00fczeyi erirken olu\u015fan s\u0131\u011f sulak oyuklar\u0131nda ya da okyanus taban\u0131ndaki volkan a\u011f\u0131zlar\u0131nda ya\u015fayan mikroorganizmalar\u0131n \u00fcretti\u011fi bir at\u0131k madde. Solunum i\u00e7in hidrojen ve karbondioksit kullan\u0131p at\u0131k olarak metan \u00fcreten bu metanojenler (yani metan \u00fcreten bakteriler) mide-ba\u011f\u0131rsak sistemimizde ya\u015fayan y\u00fczlerce bakteri t\u00fcr\u00fcnden biri ayn\u0131 zamanda. Zaten metan\u0131n k\u00fcresel \u0131s\u0131nmayla ili\u015fkisi tam da buradan kaynaklan\u0131yor. H\u00fck\u00fcmetleraras\u0131 \u0130klim De\u011fi\u015fikli\u011fi Paneli\u2019nin (IPCC) raporlar\u0131nda atmosferdeki metan\u0131n sanayi \u00f6ncesi seviyenin %50 \u00fczerine \u00e7\u0131km\u0131\u015f olmas\u0131 en az\u0131ndan k\u0131smen (%20 oran\u0131nda), s\u0131\u011f\u0131r, koyun gibi gevi\u015f getiren hayvanlar\u0131n ba\u011f\u0131rsak sistemindeki bu canl\u0131lara ba\u011flan\u0131yor. Yani yery\u00fcz\u00fcndeki metan\u0131n \u00e7ok b\u00fcy\u00fck bir k\u0131sm\u0131 oksijenin olmad\u0131\u011f\u0131 yerlerde kendine ya\u015fam alan\u0131 bulmu\u015f olan \u00e7e\u015fit t\u00fcrl\u00fc bakteriden k\u00f6ken al\u0131yor. D\u00fcnya tamam da peki ya Mars\u2019taki metan\u0131n kayna\u011f\u0131 ne?<\/span><\/p>\n

\u0130lk defa 10 y\u0131l \u00f6nce Hawaii\u2019deki Mauna Kea G\u00f6zlemevi teleskoplar\u0131n\u0131n varl\u0131\u011f\u0131ndan haberdar etti\u011fi, ancak o zamanlar veri hatas\u0131 denip fazla dikkate al\u0131nmayan Mars metan\u0131 art\u0131k yads\u0131namaz bir ger\u00e7ek haline geldi. \u0130lk \u00f6nce <\/span>New York Times<\/span><\/i> arac\u0131l\u0131\u011f\u0131yla 22 Haziran\u2019da duyurusu yap\u0131lan, ertesi g\u00fcn (23 Haziran) NASA\u2019n\u0131n resmi sitesinden yay\u0131mlanan a\u00e7\u0131klamaya g\u00f6re NASA\u2019n\u0131n y\u00fczey ke\u015fif arac\u0131 Curiosity, ge\u00e7ti\u011fimiz \u00c7ar\u015famba yapt\u0131\u011f\u0131 \u00f6l\u00e7\u00fcmlerde, k\u0131z\u0131l gezegenin atmosferinde y\u00fcksek oranda metan saptad\u0131. Daha \u00f6nceki \u00e7al\u0131\u015fmalarda eski bir g\u00f6l yata\u011f\u0131 oldu\u011fu tespit edilmi\u015f olan Gale Krateri\u2019ne 2012 A\u011fustos\u2019unda ini\u015f yapan Curiosity, metan\u0131n varl\u0131\u011f\u0131na ili\u015fkin benzer bir \u00f6l\u00e7\u00fcm\u00fc 2013\u2019te de yapm\u0131\u015f, 7ppb\u2019lik, yani atmosferdeki her 1 milyar partik\u00fclden 7\u2019sinin metana kar\u015f\u0131l\u0131k geldi\u011fi ani bir yo\u011funla\u015fma tespit etti\u011fini a\u00e7\u0131klam\u0131\u015ft\u0131. Bu son \u00f6l\u00e7\u00fcm ise 2013\u2019teki miktar\u0131n tam \u00fc\u00e7 kat\u0131: 21 ppb, yani \u015fimdiye kadar belirlenmi\u015f en y\u00fcksek seviye.<\/span><\/p>\n

Asl\u0131nda Mars\u2019\u0131n y\u00fczeyini ya\u015fam izine rastlama umuduyla aray\u0131p tarayan tek ara\u00e7 Curiosity de\u011fil. 2016\u2019da yollanan fakat ilk tespitlerinde herhangi bir sonuca ula\u015famayan Avrupa ve Rus men\u015feli Trace Gas Orbiter; Curiosity\u2019den daha \u00f6nce Mars y\u00f6r\u00fcngesine yollanm\u0131\u015f olan Avrupa Uzay Ajans\u0131\u2019n\u0131n uydular\u0131ndan Mars Express; ve yine NASA kaynakl\u0131 Mars Global Surveyor; hepsi birden g\u00f6z\u00fcn\u00fc Mars\u2019\u0131n y\u00fczeyine dikmi\u015f bakarken metan\u0131n varl\u0131\u011f\u0131na ili\u015fkin sorulara verdikleri yan\u0131t, bu gizemli gaz\u0131n Mars atmosferinde g\u00f6sterdi\u011fi mevsimsel ini\u015f \u00e7\u0131k\u0131\u015flardan dolay\u0131 olacak, tam olarak \u00f6rt\u00fc\u015fm\u00fcyor. Nitekim Curiosity\u2019nin 2013\u2019te tespit etti\u011fi 7ppb\u2019lik metan da birka\u00e7 ay boyunca varl\u0131\u011f\u0131n\u0131 koruduktan sonra aniden yok olmu\u015ftu. Mars atmosferine dair mevcut bilgi, fotokimyasal ve genel dola\u015f\u0131m modelleriyle birle\u015ftirildi\u011finde s\u00f6z konusu metan\u0131n, atmosferde homojen bir \u015fekilde da\u011f\u0131l\u0131m g\u00f6sterdi\u011fi 300 y\u0131ll\u0131k s\u00fcrenin sonunda g\u00fcne\u015f \u0131\u015f\u0131\u011f\u0131 ve kimyasal tepkimelerle par\u00e7alanm\u0131\u015f olmas\u0131 gerekiyor. Dolay\u0131s\u0131yla bug\u00fcn bu gaz\u0131n varl\u0131\u011f\u0131n\u0131 tespit etmi\u015f olmak, Mars\u2019ta ya\u015fam\u0131n varl\u0131\u011f\u0131na dair sorulara cevap vermekten \u00e7ok, daha karma\u015f\u0131k ba\u015fka sorular\u0131n sebebi haline geliyor. Ve yukar\u0131da sordu\u011fumuz soru bunlar\u0131n ba\u015f\u0131nda geliyor: Mars atmosferindeki metan\u0131n kayna\u011f\u0131 ne?<\/span><\/p>\n

Her ne kadar abiotik, yani canl\u0131l\u0131\u011fa dayanmayan, jeolojik kaynakl\u0131 metan \u00fcretim mekanizmalar\u0131 ihtimaller aras\u0131nda yer al\u0131yor olsa da Mars\u2019ta varl\u0131\u011f\u0131n\u0131 s\u00fcrd\u00fcren canl\u0131 formlar, bu sorunun en g\u00f6zde ve \u015fa\u015fal\u0131 yan\u0131t\u0131n\u0131 olu\u015fturuyor. \u00d6zellikle de Curiosity\u2019nin, ana \u00e7al\u0131\u015fma alan\u0131 Gale Krateri\u2019nde daha \u00f6nce saptad\u0131\u011f\u0131 boron ve silisyum minarelleri hesaba kat\u0131ld\u0131\u011f\u0131nda; zira bunlar, ara\u015ft\u0131rmac\u0131lar\u0131n belirtti\u011fi \u00fczere, Gale \u00fczerindeki s\u0131v\u0131 k\u00fctlesinin buharla\u015fmas\u0131ndan sonra yeralt\u0131na \u00e7ekilen su kayna\u011f\u0131n\u0131n varl\u0131\u011f\u0131na i\u015faret ediyor. Ara\u015ft\u0131rmac\u0131lar ya\u015fam\u0131n pekala burada ortaya \u00e7\u0131km\u0131\u015f olabilece\u011fini d\u00fc\u015f\u00fcn\u00fcyorlar. \u00dcstelik Gale\u2019deki tepelere t\u0131rmanan, kayalar\u0131n bile\u015fimini inceleyen, eski g\u00f6llerin ve yeralt\u0131 sular\u0131n\u0131n milyarlarca y\u0131lda nas\u0131l de\u011fi\u015fti\u011fini anlamaya \u00e7al\u0131\u015fan bu araba boyutundaki ak\u0131ll\u0131 makine, Curiosity, i\u00e7erdi\u011fi lazer tabanl\u0131 spektroskopi sayesinde \u00e7ok k\u00fc\u00e7\u00fck miktarlardaki molek\u00fclleri de tespit edebilecek kadar y\u00fcksek bir \u00e7\u00f6z\u00fcn\u00fcrl\u00fc\u011fe sahip. Dolay\u0131s\u0131yla hata pay\u0131 \u00e7ok d\u00fc\u015f\u00fck. Sonu\u00e7ta metan\u0131n kayna\u011f\u0131n\u0131 hen\u00fcz bilmiyoruz. Fakat bu sorunun cevab\u0131 \u00f6ylesine i\u015ftah kabart\u0131c\u0131 ki biri NASA, di\u011feri yine Avrupa-Rus ortak yap\u0131m\u0131 olan iki y\u00fczey tetkik arac\u0131 gelecek y\u0131l Curiosity\u2019nin yan\u0131na yollanacak. S\u00f6z\u00fcn \u00f6z\u00fc uzay ajanslar\u0131 Mars’ta ya\u015fam\u0131n s\u0131rr\u0131n\u0131 \u00e7\u00f6zene kadar durmayacak.<\/span><\/p>\n

Kaynak<\/b>
\n<\/span>1) \u201cCuriosity Detects Unusually High Methane Levels\u201d, 23 Haziran 2019, https:\/\/www.nasa.gov\/feature\/jpl\/curiosity-detects-unusually-high-methane-levels.<\/span>
\n<\/span>2) Kenneth Chang, \u201cNASA Rover on Mars Detects Puff of Gas That Hints at Possibility of Life\u201d, <\/span>The New York Times<\/span><\/i>, 22 Haziran 2019.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

K\u00fcresel \u0131s\u0131nma yaratma potansiyeli CO2\u2019in 28 kat\u0131 olan metan gaz\u0131n\u0131 \u015fimdiye kadar iklim de\u011fi\u015fimi haberlerinden okuduk, bildik. Kendisi yery\u00fcz\u00fcn\u00fcn oksijenden yoksun kimi u\u00e7 noktalar\u0131nda, mesela Alaska\u2019n\u0131n buz ve toprak kar\u0131\u015f\u0131m\u0131 y\u00fczeyi erirken olu\u015fan s\u0131\u011f sulak oyuklar\u0131nda ya da okyanus taban\u0131ndaki volkan a\u011f\u0131zlar\u0131nda ya\u015fayan mikroorganizmalar\u0131n \u00fcretti\u011fi bir at\u0131k madde. Solunum i\u00e7in hidrojen ve karbondioksit kullan\u0131p at\u0131k […]<\/p>\n","protected":false},"author":184,"featured_media":34884,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[30,19,3256],"tags":[2802,4775,1974],"class_list":["post-34882","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-astronomi","category-bilim-gundemi","category-uzay-ve-havacilik","tag-curiosity","tag-marsta-yasam","tag-metan-gazi"],"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