shairan (upagrah)

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yam (plooto) aur shairan donon apne saanjhe dravyamaan kendra ki parikrama karte hain

shairan, jise kairan bhi kahatein hain, baune grah yam (plooto) ka sab se bada upagrah hai. iski khoj 1978 mein hui thi. 2015 mein plooto aur shairan ka adhyayan karne ke liye ameriki sarkaar dvaara ek "new horaaejnj" (hindi arth: "nae kshitij") naam ka manushya-rahit antariksh yaan bhejane ki yojana hai. shairan golaakaar hai aur usaka vyaas 1,207 kimi hai, jo plooto ke vyaas ke aadhe se thoda adhik hai. usaki satah ka kul kshetrafal lagbhag 45.8 lakh varg kilometer hai. jahaaain plooto ki satah par naaitrojan aur methane ki jami gui barf hai vahaaain shairan par usaki bajaae paani ki barf hai. plooto par ek patala vaayumandal hai lekin shairan ke adhyayan se sanket mila hai ke usapar koi vaayumandal naheen hai aur usaki satah ke oopar sirf khule antariksh ka vyom hai. shairan par plooto ki tulana mein patthar kam hain aur barf adhik hai.

anukram

anya bhaashaaoain mein

is baat par matabhed hai ke shairan mein barf aur patthar ki alag-alag tahein hain ya ek hi mishran

shairan ko angreji mein "Charon" likha jaata hai.

bheetari banaavat

khagolashaastriyon mein aapas mein matabhed hai ke shairan ke andar barf aur patthar ki alag tahein hain ya poore upagrah mein ek jaisa barf aur patthar ka mishran hai. plooto aur shairan ka ghanatv dekhkar andaaja lagaaya jaata hai ke plooto ka 70% dravyamaan patthar hai jabki shairan ka keval 50-55% patthar hai. is se kuchh vaigyaaniko ki soch hai ke plooto par kisi anya vastu ke zabardast takaraav se usaka oopar ka malaba udkar ek upagrah ke roop mein ikaththa ho gaya. isliye shairan mein plooto ki oopari satah ki barf adhik hai aur plooto ke andar ke patthar kam. lekin is vichaar mein ek shanka paida hoti hai - agar vaastav mein aisa hua hota to shairan ka aur bhi bada pratishat hissa barf ka bana hona chaahiye aur plooto ka aur bhi bada pratishat hissa patthar ka. isliye kuchh anya vaigyaaniko ka maanana hai ke shairan aur plooto shuroo se hi alag vastueain theen jo takaraai, lekin fir alag hokar ek-dusare ki parikrama karne lagi.

upagrah ya judvaaain grah

plooto aur shairan ka mel saur mandal mein anokha hai. shairan ka vyaas (daayaameetar) plooto ke aadhe se zyaada hai aur usaka dravyamaan plooto ka 11.6% hai - jo saur mandal mein kisi bhi upagrah-grah ki jodi mein sabse adhik hai. tulana ke liye pruthvi ke chandrama ka vyaas pruthvi ka lagbhag ek-chauthaai aur dravyamaan pruthvi ka keval 1.2% hai. is kaaran se plooto aur shairan ka mila hua dravyamaan kendra ka bindu plooto ke andar naheen balki in donon ke beech ke khule vyom mein padta hai aur plooto aur shairan donon is bindu ki parikrama karte hain. agar khagolashaastr ki paribhaashaaeain sakhti se lagaai jaaeain to aisi sthiti mein do khagoleeya vastuon ko grah-upagrah na kehkar judvaaain grah kaha jaata hai. fir bhi aam taur par shairan ko plooto ka upagrah hi maana jaata hai.

inhein bhi dekhein