Free Astronomy Magazine January-February 2023 ARABIC VERSION

that might be embedded in a ring on your finger. Carbon is neither abundant nor scarce, making up just under 0.5% of all atoms in the entire universe. In a universe that is 75% hydrogen and 23% helium, being 25% of “everything else” certainly consti- tutes a nontrivial amount. The per- centages vary when we restrict the analysis to certain objects. Mete- orites, largely composed of iron and nickel left over from the formation of the solar system, are 1.5% carbon on average, with carbonaceous chondrites achieving higher per- centages due to the presence of or- ganic molecules and carbon-rich minerals. The Earth’s crust, domi- nated by oxygen and silicon, con- tains only 0.02% carbon. Turning to the carbon content of living organ- isms, we find humans are 18% car- bon by mass, exceeded only by the 65% oxygen mass that includes the water we carry within us – making this high carbon percentage a dra- matic localization of one element compared to the natural abun- his image of that أﺟﺴﺎم ﻣﻌﻴﻨﺔ إن . اﻷﺣﺠﺎر اﻟﻨﻴﺰﻛﻴﺔ ا ﻜﻮﻧﺔ إﱃ ﺣﺪ ﻛﺒ ﻣﻦ اﻟﺤﺪﻳـﺪ واﻟﻨﻴﻜـﻞ ا ﺘﺒﻘﻴـﺔ ﻣـﻦ ﺗﻜﻮﻳﻦ اﻟﻨﻈﺎم اﻟﺸﻤﴘ ﻫﻲ ١.٥ ٪ ﻛﺮﺑـﻮن ﰲ ا ﺘﻮﺳﻂ ، ﻣﻊ ﻛﻮﻧﺪرﻳﺖ ﻛﺮﺑﻮﻧﻲ ﺗﺤﻘﻖ ﻧﺴـﺒًﺎ أﻋ ـﲆ ﺑﺴ ـﺒﺐ وﺟ ـﻮد اﻟﺠﺰﻳﺌ ـﺎت اﻟﻌﻀ ـﻮﻳﺔ وا ﻌﺎدن اﻟﻐﻨﻴﺔ ﺑـﺎﻟﻜﺮﺑﻮن . ان رضاﻷ ﻗﴩـة اﻟﺘﻲ ﻳﻐﻠـﺐ ﻋﻠﻴﻬـﺎ اﻷﻛﺴـﺠ واﻟﺴـﻴﻠﻴﻜﻮن ﺗﺤﺘـﻮي ﻋـﲆ ٠.٠٢ ٪ ﻓﻘـﻂ ﻣـﻦ اﻟﻜﺮﺑــﻮن . ﺑﺎﻻﻧﺘﻘﺎل إﱃ ﻣ ﺤﺘـﻮى اﻟﻜﺮﺑـﻮن ﰲ اﻟﻜﺎﺋﻨـﺎت اﻟﺤﻴﺔ ﻧﺠﺪ أن اﻟﺒﴩـ ﻳﺸـﻜﻠﻮن ١٨ ٪ ﻛﺮﺑـﻮن ﺑﺎﻟﻜﺘﻠﺔ وﻻ ﻳﺘﺠﺎوزﻫﺎ ﺳـﻮى ٦٥ ٪ ﻣـﻦ ﻛﺘﻠـﺔ ــ ــــ اﻟﻜﺮﺑﻮن ﻟﻴﺲ ﻏﺮﻳﺮاً وﻻ ﻧﺎدرًا وﻳﺸـﻜﻞ أﻗـﻞ ﺑﻘﻠﻴﻞ ﻣﻦ ٠.٥ ٪ ﻣﻦ ﺟﻤﻴﻊ اﻟﺬرات ﰲ اﻟﻜـﻮن ه ﺑﺄﴎ ﰲ ﻋﺎﻟﻢ ﻳﺘﻜﻮن ﻣﻦ ٧٥ ٪ ﻫﻴﺪروﺟ و ٢٣ ٪ ﻫﻠﻴﻮم ﻓﺈن ٢٥ " ٪ ﻣـﻦ ﻛـﻞ ﳾء آﺧـﺮ " ﻳﺸﻜﻞ ﺑﺎﻟﺘﺄﻛﻴﺪ ﻛﻤﻴﺔ ﻏ ﺑﺴـﻴﻄﺔ . ﺗﺨﺘﻠـﻒ اﻟﻨﺴﺐ ا ﺌﻮﻳﺔ ﻋﻨـﺪﻣﺎ ﻧﻘﴫـ اﻟﺘﺤﻠﻴـﻞ ﻋـﲆ ــــ اﻷﻛﺴﺠ اﻟﺘﻲ ﺗﺘﻀﻤﻦ ا ﺎء اﻟﺬي ﻧﺤﻤﻠـﻪ ﰲ أﺟﺴﺎﻣﻨﺎ ﻣﻤﺎ ﻳﺠﻌﻞ ﻫﺬه اﻟﻨﺴﺒﺔ اﻟﻌﺎﻟﻴﺔ ﻣـﻦ اﻟﻜﺮﺑﻮن ﻣﻮﺿﻌًﺎ ﻣﺜ ًا ﻟﻌﻨﴫواﺣﺪ ﻣﻘﺎرﻧـﺔ إﱃ اﻟﻮﻓﺮة اﻟﻄﺒﻴﻌﻴﺔ ﰲ ا ﻮاد ﻏ اﻟﺒﻴﻮ ﻟﻮﺟﻴـﺔ اﻟﺘﻲ ﺗﺸﻜﻞ ﺳﻄﺢ اﻟﻜﻮﻛﺐ ا ﺴـﻤﻰ وﻃﻨﻨـﺎ . اﻟﺘﻘﻄــــــــــﺖﻫـــــــــــﺬﻩ اﻟﺼــــــــــﻮرة ﻟﻠﻤﻈﻠـــــــــــﺔ اﻟـــــــــــ ﺳــــــﺎﻋﺪت ﻓــــــﻲ ﺗﻮﺻــــــﻴﻞ اﻟﻤﺴــــــ ﺎراﻟﻤﺘﺠــــــﻮل ﺑ ﺳـــــــ ﻔ اﻧﺲ اﻟﺘـــــــﺎﺑﻊ ﻟﻮ ﺎﻟـــــــﺔ ﻧﺎﺳـــــــﺎ إﻟـــــــﻰ ﺳـــــــــــــﻄﺢ ﻮﻛــــــــــــــﺐ اﻟﻤـــــــــــــﺮ ﺦ ﺑﻮاﺳــــــــــــــﻄﺔ أداة ) ﻣﺎﺳﺖ ﺎم ﻓﻲ ( زد- ٦ أﺑﺮ ﻞ ٢٠٢٢ . ـﺮو ﻈﻬـﺮ اﻣﺘــﺪاد دﻟﺘــﺎ ﻧﻬـﺮﻓــﻲ ﻓﻮﻫـﺔ ﺟ ﻓﻲ ﻫﺬﻩ اﻟﺼﻮرة اﻟ ﺎﻧﻮراﻣ ﺔ اﻟﻤ ﻮﻧـﺔ ﻣـﻦ ٦٤ ﺻــﻮرة ﻣ ﻤﻌــﺔ ﻣﻌًــﺎ اﻟﺘﻘﻄــﺖ ﺑﻮاﺳــﻄﺔ ـــــــــــــــﺎﻣ ا ) ـــــــــــــــﺎم ﻣﺎﺳـــــــــــــــﻜﺖ ﻟ( زد- ﻠﻤﺴـــــــــــــــ ﺎر اﻟﻤﺘﺠــﻮل ﺑ ﺳــ ﻔ اﻧﺲ ﻓــﻲ ١١ أﺑﺮ ــﻞ ٢٠٢٢ ﻓﻲ اﻟﻴﻮم اﻟﻤﺮ ﺨﻲ ٤٠٦ ﻟﻠﻤﻬﻤﺔ .