Free Astronomy Magazine November-December 2025 ARABIC VERSION

of water has been achieved in a comet.TheALMAobservationswere then combined with data on water and other gases, observed using NASA’s Infrared Telescope Facility (IRTF),toformamorecompletepic- tureofthecomet.Bycombiningthe complementary capabilities of these twotelescopes,theresearcherswere abletomeasuremoreaccuratelythe ratio of deuterium to hydrogen (D/H)inthecomet’swater,achemi- calfingerprintthathelpsscientists trace the origins and history of waterthroughouttheSolarSystem. Remarkably,theD/Hratioofwater in12P/Pons-Brookswasfoundtobe virtuallyindistinguishablefromthat ofEarth’soceans.Themeasurement, (1.71±0.44)×10 −4 ,isthelowestsuch ratio ever measured in a Halley-type comet, and is at the lower end of values previously observed in other comets. [The value of terrestrial water is (1.5576 ± 0.0005)×10 −4 ] “Comets like this are frozen relics left over from the birth of our Solar System 4.5 billion years ago,” said Cordiner. “SinceEarthisbelievedto haveformedfrommaterialslacking I.generatedillustrationshowingacometapproach- ing Earth. [N. Lira − ALMA (ESO/NAOJ/NRAO)] NOVEMBER-DECEMBER2025 A . ﺑﻌﺪ ذﻟﻚ ﻣﺠﺖ د أرﺻﺎد أ ﻣﺮﺻﺪ ﺎ ﻣﻊ ﺑﻴﺎﻧﺎت ﻋﻦ ا ـﺎء واﻟﻐـﺎزات اﻷﺧـﺮى اﻟﺘـﻲ ر ﺻـﺪت ﺑﺎﺳﺘﺨﺪام ﻣﺮﻓـﻖ ﺗﻠﺴـﻜﻮب اﻷﺷـﻌﺔ ﺗﺤـﺖ اﻟﺤﻤﺮاء اﻟﺘﺎﺑﻊ ﻟﻨﺎﺳﺎ (IRTF) ﻟ ﺘﻜﻮﻳﻦ ﺻﻮرة أﻛﺜﺮ اﻛﺘﻤﺎﻻً ﻟﻠﻤﺬﻧﺐ وﻣﻦ ﺧﻼل اﻟﺠﻤـﻊ ﺑـ اﻟﻘ ﺪرات اﻟﺘﻜﻤﻴﻠﻴﺔ ﻟﻬﺬﻳﻦ اﻟﺘﻠﺴﻜﻮﺑ ﺗﻤﻜﻦ اﻟﺒﺎﺣﺜﻮن ﻣﻦ ﻗﻴـﺎس ﻧﺴـﺒﺔ اﻟـﺪﻳﻮﺗ ﻳﻮم إﱃ اﻟﻬﻴﺪروﺟ (D/H) ﰲ ﻣﺎء ا ﺬﻧﺐ ﺑﺪﻗﺔ أﻛﱪ وﻫﻲ ﺑﺼﻤﺔ ﻛﻴﻤﻴﺎﺋﻴﺔ ﺗﺴـﺎﻋﺪ اﻟﻌﻠﻤـﺎء ﻋـﲆ ـــــــــــــــــــــــــــــــــــــ أ ﺗﺘﺒﻊ ﺻﻮل وﺗـﺎرﻳﺦ ا ـﺎء ﰲ ﺟﻤﻴـﻊ أ ﻧﺤـﺎء اﻟﻨﻈﺎم اﻟﺸﻤﴘ . وﻣﻦ اﻟﻼﻓﺖ ﻟﻠﻨﻈﺮ أن ﻧﺴﺒﺔ D/H) ﰲ( ﻣﺎء ا ﺬﻧﺐ 12P/ ﺑﻮﻧﺲ ﺑﺮوﻛﺲ ﺗﻜﺎد ﺗﻜﻮن ﻏ ﻣﻤﻴﺰة ﻋﻦ ﺗﻠـﻚ ا ﻮﺟـﻮدة ﰲ ﻣﺤﻴﻄﺎت اﻟﻜـﺮة اﻷرﺿـﻴﺔ و ﻳﻌﺘـﱪ اﻟ سﻘﻴـﺎ ) 1.71 ± 0.44 (×10 −4 ﻫﻮ أدﻧﻰ ﻧﺴﺒﺔ ﻣﻦ ﻫﺬا اﻟﻘﺒﻴﻞ ﺗﻢ ﻗﻴﺎﺳﻬﺎ ﻋﲆ اﻹﻃﻼق ﰲ ﻣﺬﻧﺐ ﻣـﻦ ﻧﻮع ﻫﺎﱄ وﻳﻘﻊ ﺿـﻤﻦ اﻷدﻧـﻰ ﻟ ﻠﻘـﻴﻢ اﻟﺘـﻲ رﺻﺪت ﺳﺎﺑﻘ ﺎً ﰲ ﻣﺬﻧﺒﺎت أﺧﺮى . وﺑﺤﺴﺐ اﻟﻘﻴﺎﺳ ﺎت ﻓﺈن ﻗﻴﻤـﺔ ا ـﺎء اﻷرﴈ ﺗﻘﺮﻳﺒﺎً )ﻫﻲ 1.5576 ± 0.0005 (×10 −4 [. ﻗﺎلو ﻛﻮردﻳﻨﺮ " : ا ﺬﻧﺒﺎت ﻣﺜﻞ ﻫﺬه ﻫﻲ ﺑﻘﺎﻳﺎ ﻣﺘﺠﻤﺪة ﺄ ﻣﻦ ﻧﺸ ة ﻧﻈﺎﻣﻨﺎ اﻟﺸ ـ ﻤﴘ ﻗﺒﻞ 4.5 ﻣﻠﻴﺎر ﺳﻨﺔ و ﻣﻨﺬ ﻧﺸـﺄة اﻷرض ﻳﻌﺘﻘـﺪ أﻧﻬـﺎ ﺗﺸﻜﻠﺖ ﻣﻦ ﻣﻮاد ﺗﻔﺘﻘﺮ إﱃ ا ﺎء و ﻗﺪ اﻗﱰُﺣﺖ ﻣﻨﺬ ﻓـﱰة ﻃﻮﻳﻠـﺔ أن اﺻـﻄﺪاﻣﺎت ا ـﺬﻧﺒﺎت ﻛﺎﻧﺖ ﻣﺼﺪر اً ﻣﺤﺘﻤﻼً ﻴـﺎه اﻷر وﻣـﺎ ض زال اﻟﻌﻠﻤﺎء ﻳﺪرﺳﻮن ﻫﺬه اﻟﻔﺮﺿﻴﺔ . رﺳـﻢ ﺗﻮﺿــﻴﺤﻲ ﺗـﻢ إﻧﺘﺎﺟـﮫ ﺎﻟـﺬ ﺎء اﻻﺻـﻄﻨﺎﻋﻲ ﻳﻮﺿــﺢ ﺎً ﻣـﺬﻧ أﺛﻨــﺎء ـﮫ اﻗ ا ﻣﻦ اﻟﻜﺮة اﻷرﺿ ﺔ . [ N. Lira − ALMA (ESO/NAOJ/NRAO)] ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 31 ﻧﻮﻓﻤﺒﺮ - ﺩﻳﺴﻤﺒﺮ 2 0 2 5