{"id":39055,"date":"2019-12-16T09:58:56","date_gmt":"2019-12-16T06:58:56","guid":{"rendered":"https:\/\/bilimvegelecek.com.tr\/?p=39055"},"modified":"2019-12-16T10:00:25","modified_gmt":"2019-12-16T07:00:25","slug":"cuce-gezegen-nedir","status":"publish","type":"post","link":"https:\/\/bilimvegelecek.com.tr\/index.php\/2019\/12\/16\/cuce-gezegen-nedir","title":{"rendered":"C\u00fcce Gezegen nedir?"},"content":{"rendered":"

21.y\u00fczy\u0131l\u0131n ilk be\u015f y\u0131l\u0131nda G\u00fcne\u015f Sistemi\u2019nde ger\u00e7ekle\u015ftirilen baz\u0131 ke\u015fifler bilim insanlar\u0131n\u0131 \u201cgezegen\u201d tan\u0131m\u0131n\u0131 g\u00f6zden ge\u00e7irmeye zorlam\u0131\u015ft\u0131r. 2006\u2019da toplanan Uluslararas\u0131 Astronomi Birli\u011fi\u2019nce de baz\u0131 yeni tan\u0131mlar yap\u0131lm\u0131\u015ft\u0131r. Buna g\u00f6re bir g\u00f6kcisminin gezegen olabilmesi i\u00e7in \u00fc\u00e7 temel \u00f6l\u00e7\u00fct\u00fc sa\u011flamas\u0131 gerekmektedir:
\n1) G\u00fcne\u015f\u2019in (ya da bir ba\u015fka y\u0131ld\u0131z\u0131n) \u00e7evresinde d\u00f6n\u00fcyor olmal\u0131d\u0131r.
\n2) K\u00fcresel bir yap\u0131s\u0131 olacak denli k\u00fctlesi b\u00fcy\u00fck olmal\u0131d\u0131r.
\n3) Yak\u0131n \u00e7evresini \u201ctemizlemi\u015f\u201d olmal\u0131d\u0131r.<\/p>\n

Burada \u201ctemizlemi\u015f olmak\u201dtan anla\u015f\u0131lan \u015fey, bulundu\u011fu b\u00f6lgede -y\u00f6r\u00fcngesi civar\u0131nda- k\u00fctle\u00e7ekimsel olarak egemen olmas\u0131, yani yak\u0131n \u00e7evresinde kendisine yak\u0131n b\u00fcy\u00fckl\u00fckte ba\u015fka g\u00f6kcisimlerinin olmamas\u0131d\u0131r. Bir g\u00f6kcisminin c\u00fcce gezegen olabilmesi i\u00e7in ise, yukar\u0131daki ko\u015fullardan ilk ikisini sa\u011flamas\u0131 yeterlidir. Ancak bunlara ek olarak herhangi bir g\u00f6kcisminin uydusu olmamas\u0131 da gerekir. C\u00fcce gezegenlerin k\u00fctlesinin alt ve \u00fcst s\u0131n\u0131rlar\u0131 tan\u0131mlanmam\u0131\u015ft\u0131r. Alt s\u0131n\u0131r\u0131 \u201ck\u00fcresel yap\u0131\u201dy\u0131 sa\u011flayacak olan hidrostatik denge belirler. Ne var ki hidrostatik denge de g\u00f6kcisminin i\u00e7eri\u011fine ba\u011fl\u0131d\u0131r.<\/p>\n

G\u00fcne\u015f Sistemi\u2019nde \u015fimdilik 5 c\u00fcce gezegen bulunuyor: Ceres (\u00e7ap\u0131 975 km), Pl\u00fcton (\u00e7ap\u0131 2300 km), Eris (\u00e7ap\u0131 2400-2600 km aras\u0131nda), Haumea (\u00e7ap\u0131 1050-1400 km aras\u0131nda) ve MakeMake (\u00e7ap\u0131 1300-1900 km aras\u0131nda). Ancak Kuiper Ku\u015fa\u011f\u0131 olarak bilinen b\u00f6lgede, hen\u00fcz g\u00f6zlemlenmemi\u015f 40-200 aras\u0131nda c\u00fcce gezegen olabilece\u011fi tahmin ediliyor. Hatta ileride Kuiper Ku\u015fa\u011f\u0131\u2019n\u0131n \u00f6tesi de incelenebildi\u011finde, bu say\u0131n\u0131n 2000\u2019e kadar \u00e7\u0131kabilece\u011fi d\u00fc\u015f\u00fcn\u00fcl\u00fcyor.<\/p>\n

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\u00dcstte Pl\u00fcton ve \u00fc\u00e7 uydusu ile a\u015fa\u011f\u0131da Haumea ve iki uydusu g\u00f6r\u00fcl\u00fcyor.<\/figcaption><\/figure>\n

20.y\u00fczy\u0131l\u0131n ba\u015flar\u0131nda ke\u015ffedilen Pl\u00fcton 2006\u2019ya kadar gezegen kabul ediliyordu. En uzak ve en k\u00fc\u00e7\u00fck gezegen oydu. G\u00fcne\u015f\u2019ten D\u00fcnya\u2019ya 8 dakika 20 saniyede gelen g\u00fcne\u015f \u0131\u015f\u0131nlar\u0131 D\u00fcnya\u2019n\u0131n y\u00fczde 0,6\u2019s\u0131 kadar b\u00fcy\u00fck olan Pl\u00fcton\u2019a 5 saatten uzun bir s\u00fcrede ancak ula\u015f\u0131r. Pl\u00fcton art\u0131k bir c\u00fcce gezegen olarak kabul ediliyor. G\u00fcne\u015f\u2019e 5,9 milyar kilometre uzaktaki bu c\u00fcce gezegenin d\u00f6rt uydusu vard\u0131r: Charon, Nix, Hydra ve S\/2011P1. \u0130kinci c\u00fcce gezegen Ceres 1801\u2019de -bug\u00fcn Asteroit Ku\u015fa\u011f\u0131 olarak bilinen b\u00f6lgede- ke\u015ffedilmi\u015f ve ilk \u00f6nce gezegen olarak s\u0131n\u0131fland\u0131r\u0131lm\u0131\u015ft\u0131r. Ancak o b\u00f6lgede s\u00fcrekli yeni ve k\u00fc\u00e7\u00fck g\u00f6kcisimlerinin ke\u015ffedilmesi g\u00f6kbilimcileri rahats\u0131z etmi\u015ftir. Sonunda yeni bulunanlarla birlikte gezegen say\u0131s\u0131 20\u2019yi a\u015f\u0131nca Ceres ve son bulunan \u201cminik\u201d gezegenler 1822\u2019de gezegenlikten \u00e7\u0131kart\u0131lm\u0131\u015f ve o zaman i\u00e7in yeni kabul edilen \u201casteroit\u201d s\u0131n\u0131f\u0131na sokulmu\u015ftur. 2006\u2019da yap\u0131lan c\u00fcce gezegen tan\u0131m\u0131na uydu\u011fu i\u00e7in de art\u0131k bir kez daha kategori de\u011fi\u015ftirmi\u015f ve c\u00fcce gezegen olarak s\u0131n\u0131fland\u0131r\u0131lmaya ba\u015flanm\u0131\u015ft\u0131r.<\/p>\n

G\u00fcne\u015f Sistemi\u2019nin \u00fc\u00e7\u00fcnc\u00fc c\u00fcce gezegeni Eris\u2019tir. \u0130lk kez Ocak 2005\u2019te g\u00f6zlemlenen Eris, Pl\u00fcton\u2019dan daha b\u00fcy\u00fckt\u00fcr. \u015eimdilik en b\u00fcy\u00fck ve en uzak c\u00fcce gezegen olan Eris\u2019in, Dysnomia adl\u0131 bir uydusu vard\u0131r. Eris, G\u00fcne\u015f\u2019in \u00e7evresindeki bir turunu 557 y\u0131lda tamamlar. 2010\u2019da G\u00fcne\u015f\u2019e en uzak konumunda yer alm\u0131\u015ft\u0131r (97,5 AB).<\/p>\n

D\u00f6rd\u00fcnc\u00fc c\u00fcce gezegen Haumea, t\u0131pk\u0131 Pl\u00fcton gibi, Kuiper Ku\u015fa\u011f\u0131\u2019ndaki c\u00fcce gezegenlerden biridir. Kuiper Ku\u015fa\u011f\u0131, Asteroit Ku\u015fa\u011f\u0131\u2019na benzeyen bir ku\u015fakt\u0131r. Yap\u0131lan hesap ve tahminlere g\u00f6re, i\u00e7inde binlerce g\u00f6kcismi bulunur. B\u00f6yle bir ku\u015fa\u011f\u0131n var olmas\u0131 gerekti\u011fi 1930\u2019lu y\u0131llardan beri zaman zaman ileri s\u00fcr\u00fclm\u00fc\u015ft\u00fcr. Ne var ki \u201cku\u015fak\u201d 1951\u2019de konuyla ilgili bir makale yay\u0131mlayan Gerard P. Kuiper\u2019\u0131n ad\u0131yla an\u0131l\u0131r: Halbuki kendisi g\u00fcn\u00fcm\u00fczde b\u00f6yle bir ku\u015fa\u011f\u0131n kalmad\u0131\u011f\u0131n\u0131 d\u00fc\u015f\u00fcn\u00fcyordu. 1990\u2019l\u0131 y\u0131llara kadar b\u00f6yle bir ku\u015fa\u011f\u0131n varl\u0131\u011f\u0131n\u0131 g\u00f6steren hi\u00e7bir g\u00f6kcismi saptanamam\u0131\u015ft\u0131r. Sonunda 1990\u2019l\u0131 y\u0131llar\u0131n ba\u015f\u0131nda ilk Kuiper Ku\u015fa\u011f\u0131 cismi g\u00f6r\u00fcld\u00fc. Sonra ke\u015fiflerin arkas\u0131 kesilmedi ve Kuiper Ku\u015fa\u011f\u0131\u2019n\u0131n varl\u0131\u011f\u0131 kesin olarak kan\u0131tland\u0131. Buras\u0131, G\u00fcne\u015f\u2019e 30-55 AB uzakl\u0131kta (4,5-7,5 milyar km aral\u0131\u011f\u0131nda) simit \u015feklinde bir b\u00f6lgedir. Asteroit Ku\u015fa\u011f\u0131\u2019ndan yakla\u015f\u0131k 20 kat daha geni\u015ftir ve g\u00f6kcisimlerinin toplam k\u00fctlesi de 20-200 kat daha b\u00fcy\u00fckt\u00fcr. T\u0131pk\u0131 Asteroit Ku\u015fa\u011f\u0131 gibi G\u00fcne\u015f Sistemi\u2019nin olu\u015fumundan kalan \u201ck\u00fc\u00e7\u00fck\u201d d\u00f6k\u00fcnt\u00fcleri i\u00e7erir. Ancak bu ku\u015faktaki g\u00f6kcisimleri asteroitlerden daha b\u00fcy\u00fckt\u00fcr ve yap\u0131lar\u0131 da daha \u00e7ok kuyrukluy\u0131ld\u0131zlar\u0131n yap\u0131s\u0131n\u0131 and\u0131r\u0131r: Buzdand\u0131rlar. G\u00f6kbilimciler bu b\u00f6lgede \u00e7ap\u0131 100 km\u2019nin \u00fcst\u00fcnde 70.000\u2019i a\u015fk\u0131n g\u00f6kcismi oldu\u011funu tahmin ediyor. Ne var ki hepsinin toplam k\u00fctlesi D\u00fcnya\u2019n\u0131n ancak onda biri kadard\u0131r.<\/p>\n

 <\/p>\n

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Nept\u00fcn\u2019\u00fcn y\u00f6r\u00fcngesinden sonra ba\u015flayan, 30-55 AB aral\u0131\u011f\u0131nda yer alan, simit \u015feklindeki b\u00f6lgeye Kuiper Ku\u015fa\u011f\u0131 denir.<\/figcaption><\/figure>\n

T\u0131pk\u0131 Pl\u00fcton gibi bir ba\u015fka c\u00fcce gezegen Haumea da bu ku\u015fa\u011f\u0131n bir \u00fcyesidir. Haumea 2004\u2019te ke\u015ffedilmi\u015ftir. Hi\u2019iaka ve Namaka adl\u0131 iki uydusu vard\u0131r. Haumea\u2019n\u0131n y\u00f6r\u00fcngesi G\u00fcne\u015f\u2019ten ortalama 43 AB uzakl\u0131ktad\u0131r. G\u00fcne\u015f\u2019in \u00e7evresindeki bir turunu 283 y\u0131lda tamamlar.<\/p>\n

Mart 2005\u2019te ke\u015ffedilen ve bir Kuiper Ku\u015fa\u011f\u0131 cismi olan MakeMake sonuncu c\u00fcce gezegendir. Hi\u00e7 uydusu yoktur. MakeMake\u2019nin y\u00f6r\u00fcngesi G\u00fcne\u015f\u2019ten ortalama 52 AB uzakl\u0131ktad\u0131r. Bu c\u00fcce gezegen G\u00fcne\u015f\u2019in \u00e7evresindeki bir turunu 310 y\u0131lda tamamlar.<\/p>\n

Kaynak:<\/strong> \u00c7a\u011flar Sunay, 50 Soruda Evren, Bilim ve Gelecek Kitapl\u0131\u011f\u0131, Ekim 2011, 1. Bask\u0131, s.140-144<\/p>\n","protected":false},"excerpt":{"rendered":"

21.y\u00fczy\u0131l\u0131n ilk be\u015f y\u0131l\u0131nda G\u00fcne\u015f Sistemi\u2019nde ger\u00e7ekle\u015ftirilen baz\u0131 ke\u015fifler bilim insanlar\u0131n\u0131 \u201cgezegen\u201d tan\u0131m\u0131n\u0131 g\u00f6zden ge\u00e7irmeye zorlam\u0131\u015ft\u0131r. 2006\u2019da toplanan Uluslararas\u0131 Astronomi Birli\u011fi\u2019nce de baz\u0131 yeni tan\u0131mlar yap\u0131lm\u0131\u015ft\u0131r. Buna g\u00f6re bir g\u00f6kcisminin gezegen olabilmesi i\u00e7in \u00fc\u00e7 temel \u00f6l\u00e7\u00fct\u00fc sa\u011flamas\u0131 gerekmektedir: 1) G\u00fcne\u015f\u2019in (ya da bir ba\u015fka y\u0131ld\u0131z\u0131n) \u00e7evresinde d\u00f6n\u00fcyor olmal\u0131d\u0131r. 2) K\u00fcresel bir yap\u0131s\u0131 olacak denli k\u00fctlesi […]<\/p>\n","protected":false},"author":429,"featured_media":39056,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[19],"tags":[482,3270,657,795,5667,4416,2347],"class_list":["post-39055","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-bilim-gundemi","tag-bilim","tag-cuce-gezegen","tag-evren","tag-gunes","tag-haumea","tag-kuiper-kusagi","tag-pluton"],"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