Free Astronomy Magazine November-December 2024 ARABIC VERSION

W More black holes than expectedin the early Universe byNASA − RayVillard ith the help of NASA’s HubbleSpaceTelescope, aninternationalteamof researchers led by scientists in the DepartmentofAstronomyatStock- holm University has found more black holes in the early universe thanhaspreviouslybeenreported. The new result can help scientists understandhowsupermassiveblack holeswerecreated.Currently,scien- tistsdonothaveacompletepicture ofhowthefirstblackholesformed not long after the big bang. It is known that supermassive black holes, that can weigh more than a billion suns, exist at the center of several galaxies less than a billion years after the big bang. “Many of theseobjectsseemtobemoremas- sivethanweoriginallythoughtthey couldbeatsuchearlytimes—either they formed very massive or they grewextremelyquickly,” saidAlice Young, a PhD student from Stock- holm University and co-author of the study published in The Astro- physical Journal Letters . Blackholesplayanimportantrolein thelifecycleofallgalaxies,butthere are major uncertainties in our un- derstanding of how galaxies evolve. In order to gain a complete picture of the link between galaxy andblackholeevolution,theresearche rs used Hubble to survey how many black holes exist among a popula- tion of faint galaxies when the uni- verse was just a few percent of its current age. Initialobservationsofthesurveyre- gionwerere-photographedbyHub- bleafterseveralyears.Thisallowed the team to measure variations in the brightness of galaxies. These variations are a telltale signof black holes. The team identified more black holes than previously found by other methods. The new observational results sug- gest that some black holes likely formed by the collapse of massive, pristinestarsduringthefirstbillion years of cosmic time. These types of stars can only exist at very early timesintheuniverse,becauselater- generation stars are polluted by the remnants of stars that have already lived and died. Other alternativesfor black hole formation include collapsing gas clouds, mergers of stars in massive clusters, and “pri- mordial” black holes that formed(by physically speculative mecha- nisms) in the first few seconds after the big bang. With this new infor- mation about black hole formation, more accurate models of galaxy for- mation can be constructed. “The formation mechanism of early blackholesisanimportantpartof اﻟ ﺜﻘﻮب اﻟ ﺴﻮداء ﻓﻲ ﺪا ﺔ اﻟ ﻮن أﻛ ﻣﻦ اﻟﻤﺘﻮﻗﻊ : ﻘﻠﻢ راي ﻓ ﻼرد – و ﺎﻟﺔ ﻧﺎﺳﺎ 20 ﺗﻤﻜﻦ ﻓﺮﻳﻖ دوﱄ ﻣﻦ اﻟﺒـﺎﺣﺜ ﺑﻤﺴـﺎﻋﺪة ﺗﻠﺴﻜﻮب ﻫ ﺎﺑﻞ اﻟﻔﻀﺎﺋﻲ اﻟﺘﺎﺑﻊ ﻟﻮﻛﺎﻟﺔ ﻧﺎﺳﺎ و ﺑﻘﻴﺎدة ﻋﻠﻤﺎء ﻣﻦ ﻗﺴﻢ ﻋﻠﻢ اﻟﻔﻠﻚ ﺑﺠﺎﻣﻌﺔ ﺳﺘﻮﻛﻬﻮﻟﻢ ﻣﻦ اﻛﺘﺸﺎف ا ﺰﻳﺪ ﻣﻦ اﻟﺜﻘـﻮب اﻟﺴﻮداء ﰲ اﻟ ﻜﻮن ا ﺒﻜﺮ ﻣﻘﺎرﻧـﺔ ﺑﻤـﺎ ﺗـﻢ اﻹ ﻋﻼن .ﺎ ﻋﻨﻪ ﺳﺎﺑﻘ ﻳﻤﻜﻦ أن ﺗﺴﺎﻋﺪ اﻟﻨﺘﻴﺠﺔ اﻟﺠﺪﻳﺪة اﻟﻌﻠﻤﺎء ﰲ ﻓﻬﻢ ﻛﻴﻔﻴﺔ ﺗﺸﻜﻞ اﻟﺜﻘﻮب اﻟﺴﻮداء ﻓﺎﺋﻘـﺔ اﻟﻜﺘﻠﺔ . ﰲ اﻟﻮﻗـﺖ اﻟﺤـﺎﱄ ﻻ ﻳﻤﻠـﻚ اﻟﻌﻠﻤـﺎء ﺻﻮرة ﻛﺎﻣﻠﺔ ﻋﻦ ﻛﻴﻔﻴـﺔ ﺗﺸـﻜﻞ اﻟﺜﻘـﻮب اﻟﺴﻮداء اﻷوﱃ ﺑﻌﺪ ﻓﱰة وﺟﻴﺰة ﻣﻦ اﻻﻧﻔﺠﺎر اﻟﻌﻈﻴﻢ . ﻣﻦ ا ﻌﺮوف أن اﻟﺜﻘـﻮب اﻟﺴـﻮداء ﻓﺎﺋﻘﺔ اﻟﻜﺘﻠﺔ اﻟﺘ ﻲ ﻳﻤﻜﻦ أن ﺗﺰن أﻛﺜـﺮ ﻣـﻦ ﻣﻠﻴﺎ ر ﺷﻤﺲ ﻣﻮﺟﻮدة ﰲ ﻣﺮﻛﺰ اﻟﻌﺪﻳﺪ ﻣـﻦ ا ﺠﺮات ﺑﻌﺪ أﻗﻞ ﻣﻦ ﻣﻠﻴﺎر ﻋﺎم ﻣﻦ ا ﻻﻧﻔﺠﺎر اﻟﻌﻈﻴﻢ . ﻗﺎﻟﺖ أﻟﻴﺲ ﻳـﻮﻧﺞ ﻃﺎﻟﺒـﺔ اﻟـﺪﻛﺘﻮراه ﻣـﻦ ﺟﺎﻣﻌ ـﺔ ﺳـﺘﻮﻛﻬﻮﻟﻢ وا ﺆﻟﻔــﺔ ا ﺸـﺎرﻛﺔ ﻟﻠﺪراﺳــﺔ ا ﻨﺸــﻮرة ﰲ رﺳــﺎﺋﻞ ا ﺠﻠــﺔ اﻟﻔﻴﺰﻳﺎﺋﻴ ـﺔ اﻟﻔﻠﻜﻴ ـ :" ﺔ ﺣﻘﻴﻘــﺔ ﻳﺒ ـﺪو أن اﻟﻌﺪﻳﺪ ﻣﻦ ﻫـﺬه اﻷﺟـﺮام اﻟﺴـﻤﺎوﻳﺔ أﻛﺜـﺮ ﺎﻣﺔ ﺿﺨ ﻣﻤﺎ ﰲ اﻷﺻﻞ ﻛﻨﺎ ﻧﻌﺘﻘﺪ وﻳﺤﺘﻤـﻞ أﻧﻬﺎ ﰲ اﻷوﻗﺎت ا ﺒﻜـﺮة إﻣـﺎ أﻧﻬـﺎ ﺗﺸـﻜ ﻠﺖ ﺛﻘﻴﻠﺔ أو ﺟﺪاً رﺑﻤﺎ أﻧﻬﺎ ـ ﻧﻤﺖ ﺑ . ﻋﺎﻟﻴﺔ ﴪﻋﺔ ـ ﺗﻠﻌﺐ اﻟﺜﻘﻮب اﻟﺴﻮداء دوراً ﻣﻬﻤـﺎً ﰲ دورة ﺣﻴﺎة ا ﺠﺮ ات وﻟﻜﻦ ﻫﻨﺎك ﺷﻜﻮك ﻛﺒـ ة ﰲ ﻓﻬﻤﻨﺎ ﻟﻜﻴﻔﻴﺔ ﺗﻄـﻮر ا ﺠـﺮات . ﻣـﻦ أﺟـﻞ اﻟﺤﺼﻮل ﻋﲆ ﺻـﻮرة ﻛﺎﻣﻠـﺔ ﻟﻠـﺮاﺑﻂ ﺑـ ﺗﻄﻮر ا ﺠﺮات واﻟﺜﻘﻮب اﻟﺴﻮداء اﺳـﺘﺨﺪم اﻟﺒﺎﺣﺜﻮن ﻫﺎﺑﻞ ﺴﺢ ﻋﺪد اﻟﺜﻘﻮب اﻟﺴﻮداء ا ﻮﺟﻮدة ﺑ ﻣﺠﻤﻮﻋﺔ ﻣﻦ ا ﺠﺮات اﻟﺨﺎﻓﺘﺔ ﻋﻨﺪﻣﺎ ﻛﺎن ﻋﻤﺮ اﻟﻜﻮن ﻧﺴﺒﺔ ﻗﻠﻴﻠـﺔ ﻓﻘـﻂ ﻣﻦ ﻋﻤﺮه اﻟﺤﺎﱄ . ﻟ ﻘﺪ أﻋﺎد ﺗﻠﺴﻜﻮب ﻫﺎﺑﻞ ﺗﺼـﻮﻳﺮ اﻷرﺻـﺎد اﻷ وﻟﻴﺔ ﻨﻄﻘﺔ ا ﺴـﺢ ﺑﻌـﺪ ﻋـﺪة ﺳـﻨﻮات وﺳﻤﺢ ﻫﺬا ﻟﻠﻔﺮﻳﻖ ﺑ ﻘﻴـﺎس اﻻﺧﺘﻼﻓـﺎت ﰲ ﺳﻄﻮع ا ﺠـﺮات وﺗﻌـﺪ ﻫـﺬه اﻻﺧﺘﻼﻓـﺎت ﻋﻼﻣﺔ واﺿﺤﺔ ﻋﲆ وﺟﻮد اﻟﺜﻘﻮب اﻟﺴـﻮداء وﻗﺪ ﺣﺪد اﻟﻔﺮﻳﻖ ﻋـﺪد اً أﻛـﱪ ﻣـﻦ اﻟﺜﻘـﻮب اﻟﺴ ﻮداء ﻣﻘﺎرﻧﺔ ﺑﻤﺎ ﺗـﻢ اﻛﺘﺸـﺎﻓﻪ ﺳـﺎﺑﻘ ﺎً ﺑﺎﺳﺘﺨﺪ ام ﻃﺮق أﺧﺮى . ﺗﺸ ﻧﺘﺎﺋﺞ اﻟﺮﺻـﺪ اﻟﺠﺪﻳـﺪة إﱃ أن ﺑﻌـﺾ اﻟﺜﻘﻮب اﻟﺴﻮداء رﺑﻤﺎ ﺗﻜﻮﻧﺖ ﻧﺘﻴﺠﺔ ﻻﻧﻬﻴﺎر ﻧﺠﻮم ﺿﺨﻤﺔ ﺧﻼل ا ﻠﻴﺎر ﺳـﻨﺔ اﻷوﱃ ﻣـﻦ اﻟﺰﻣﻦ اﻟﻜﻮﻧﻲ و ﻻ ﻳﻤﻜﻦ أن ﺗﻮﺟﺪ ﻣﺜﻞ ﻫـﺬه اﻷﻧـﻮاع ﻣـﻦ اﻟﻨﺠـﻮم إﻻ ﰲ أوﻗـﺎت ﻣﺒﻜـﺮة ﻟﻠﻐﺎﻳﺔ ﰲ اﻟﻜـﻮن وذﻟـﻚ ﻷن ﻧﺠـﻮم اﻟﺠﻴـﻞ اﻟﻼﺣﻖ ﻣﻠﻮﺛﺔ ﺑﺒﻘﺎﻳ ﺎ اﻟﻨﺠﻮم اﻟﺘـﻲ ﻋﺎﺷـﺖ وﻣﺎﺗﺖ ﺑﺎﻟﻔﻌﻞ . وﻣﺎﺗﺖ ﺑﺎﻟﻔﻌﻞ إن . اﻟﺒﺪاﺋﻞ اﻷﺧﺮى ﻟﺘﻜـﻮﻳﻦ اﻟﺜﻘﻮب اﻟﺴﻮداء ﺗﺸﻤﻞ اﻧﻬﻴﺎر ﺳﺤﺐ اﻟﻐﺎز واﻧـﺪﻣﺎج اﻟﻨﺠـﻮم ﰲ ﻣﺠﻤﻮﻋـﺎت ﺿـﺨﻤﺔ واﻟﺜﻘﻮب اﻟﺴﻮداء اﻟﺒﺪاﺋﻴﺔ " " اﻟﺘﻲ ﺗﺸـﻜﻠﺖ ) ﺑﺎﺳﺘﺨﺪام آﻟﻴـﺎت ﺗﺨﻤﻴﻨﻴـﺔ ﻓﻴﺰﻳﺎﺋﻴـﺔ ﰲ ( اﻟﺜﻮاﻧﻲ اﻟﻘ ﻠﻴﻠﺔ اﻷوﱃ ﺑﻌﺪ ﺣﺪوث اﻻﻧﻔﺠـﺎر اﻟﻌﻈﻴﻢ وﺑﻔﻀﻞ ﻫـﺬه ا ﻌﻠﻮﻣـﺎت ا ﻟﺠﺪﻳـﺪة ﺣﻮل ﺗﻜﻮﻳﻦ اﻟﺜﻘﻮب اﻟﺴﻮداء ﻳﻤﻜـﻦ ﺑﻨـﺎء ﻧﻤﺎذج أﻛﺜﺮ دﻗﺔ ﻟﺘﻜﻮﻳﻦ ا ﺠﺮات . إن آ ﻓﻬﻢ ﻟﻴﺔ ﺗﻜـﻮﻳﻦ اﻟﺜﻘـﻮب اﻟﺴـﻮداء ﰲ اﻟﻜﻮن ا ﺒﻜﺮ ﺗﺸﻜﻞ ﺟﺰء اً ﺎً ﻣﻬﻤـ ﻣـﻦ ﻟﻐـﺰ ﺗﻄﻮر ا ﺠﺮات . ﻧﻮﻓﻤﺒﺮ - ﺩﻳﺴﻤﺒﺮ 2 0 2 4