Free Astronomy Magazine March-April 2026 ARABIC VERSION

“Weknowfromtheorythatmostofthe massintheUniverseisexpected tobedarkmatter,butit’sdifficult todetectthisdarkmaterialbecause itdoesn’temitlight.Cloud-9gives usararelookatadark-matter-dom- inatedcloud.” Theobjectiscalleda Reionization-Limited H I Cloud, or “RELHIC.”Theterm“HI”refersto neutralhydrogen,and“RELHIC”de- scribesanatalhydrogencloudfrom the Universe’s early days, a fossil leftover that has not formed stars. For years, scientists have looked for evidence of such a theoretical phan- tom object. It wasn’t until they turned Hubble toward the cloud, confirming that it is indeed starless, that they found support for the the- ory. “Before we used Hubble, you couldarguethatthisisafaintdwarf galaxythatwecouldnotseewith ground-based telescopes. They just didn’t go deep enough in sensitivity touncoverstars,” explainedleadau- thor Gagandeep Anand of STScI. “But with Hubble’s Advanced Cam-era for Surveys, we’re able to nail down that there’s nothing there.” Thediscoveryofthisreliccloudwasa surprise. “Among our galactic neigh- bors, there might be a few aban- donedhousesoutthere,” saidSTScI’s Rachael Beaton, who is also on the research team. RELHICs are thought to be dark matter clouds that were not able to accumulate enough gasto form stars. They represent a win- dow into the early stages of galaxy formation. Cloud-9 suggests the existenceof many other small, dark matter-dom- inatedstructuresintheUniverse— otherfailedgalaxies.Thisdiscovery provides new insights into the dark componentsoftheUniversethatare difficulttostudythroughtraditional observations,whichfocusonbright objects like stars and galaxies. 13 ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ ﻫﺬه اﻟﺴﺤﺎﺑﺔ ﻧﺎﻓﺬة ﻋﲆ اﻟﻜﻮن ا ﻈﻠﻢ ﻛﺬﻟﻚ ﻧﻌﻠﻢ ﻣﻦ اﻟﻨﻈﺮﻳﺔ ﻣ نأ ﻌﻈـﻢ ﻛﺘﻠـﺔ اﻟ ﻜـﻮن ﻳ ﺘﻮﻗﻊ أن ﻳ ﻜﻮن ﻣـﺎدة ﻣﻈﻠﻤـﺔ ﻟﻜـﻦ ﻣـﻦ اﻟﺼﻌﺐ ﻋﻠﻤﻴﺎً رﺻـﺪ ﻫـﺬه ا ـﺎدة ﻷﻧﻬـﺎ ﻻ ﺗﺼﺪر اﻟﻀﻮء . ﺗﻤﻨﺤﻨﺎ اﻟﺴﺤﺎﺑﺔ 9- ﻓﺮﺻـﺔ ﻧﺎدرة ﻟﺪراﺳﺔ ﺳﺤﺎﺑﺔ ﺗ ﻬﻴﻤﻦ ﻋﻠﻴﻬـﺎ ا ـﺎدة ا ﻈﻠﻤﺔ ﻳ. ﻄﻠﻖ ﻋﲆ ﻫﺬا اﻟﺠﺮم ﺳـﺤﺎﺑﺔ H I ﻣﺤــﺪودة ﺑﺈﻋــﺎدة اﻟﺘــﺄﻳﻦ أو RELHIC اﺧﺘﺼﺎرا " ﻳﺸ ﺣﻴﺚ I H" اﻟﻬ إﱃ ﻴﺪروﺟ ا ﺤﺎﻳ ﺪ ا ﺤﺎﻳـﺪ ﺑﻴﻨﻤـﺎ ﺗﺼـﻒ RELHIC ﺳـﺤﺎﺑﺔ ﻫﻴﺪروﺟ ﻣﺤﺎﻳﺪ أﺛﺮﻳﺔ ﻣﺤـﺪودة ﺑﺈﻋـﺎدة اﻟﺘﺄﻳﻦ أي ﺑﻘﺎﻳﺎ ﻟـ ﻢ ﺗﺘﺸـﻜﻞ ﻓﻴﻬـﺎ ﻧﺠـﻮم . ﻟﺴﻨﻮات ﻃﻮﻳﻠﺔ ﺑﺤﺚ اﻟﻌﻠ ﻤﺎ ء ﻋﻦ أدﻟﺔ ﻋـﲆ وﺟﻮد ﻣﺜﻞ ﻫﺬا اﻟﺠﺴﻢ اﻟﺒﺎﻫـﺖ وﻟـﻢ ﻳﻜـﻦ اﻟﺘﺄﻛﻴﺪ إﻻ ﻋﻨﺪﻣ ﺎ وﺟﻬـﻮا ﺗﻠﺴـﻜﻮب ﻫﺎﺑـﻞ ﻧﺤﻮ اﻟﺴﺤﺎﺑﺔ ﻟﺘﺜﺒﺖ أﻧﻬﺎ ﺧﺎﻟﻴﺔ ﻣﻦ اﻟﻨﺠﻮم وﻫﻮ ﻣﺎ دﻋﻢ اﻟﻨﻈﺮﻳﺔ . ﻛـﺬﻟﻚ ﻗـﺎل ا ﺆﻟـﻒ اﻟﺮﺋﻴﴘ ﺟﺎﺟﺎﻧﺪﻳﺐ أﻧﺎﻧﺪ ﻣﻦ ﻣﻌﻬـﺪ ﻋﻠـﻮم ﺗﻠﺴﻜﻮب اﻟﻔﻀﺎء :" ﻗﺒﻞ اﺳـﺘﺨﺪام ﻫﺎﺑـﻞ، ﻛﺎن ﻳﻤﻜﻦ اﻟﺠﺪال ﺑـﺄن ﻫـﺬه ر ﺑﻤـﺎ ﺗﻜـﻮن ﺗﻠﺴﻜﻮﺑﺎت اﻟﻔﻀﺎء :" ﺑﺎﺳﺘﺨﺪام ﺗﻠﺴـﻜﻮب ﻫﺎﺑﻞ ﻛﺎن ﻳﻤﻜﻦ اﻟﻘﻮل اﻫﺬ نأ اﻟﺠﺴـ ﻢ ﻗـﺪ ﻜﻮن ﻳ ﻣﺠﺮة ﻗﺰﻣﺔ ﺑﺎﻫﺘﺔ ﻟـﻢ ﻧـﺘﻤﻜﻦ ﻣـﻦ رؤ ﻳﺘﻬـــﺎ ﺑﺎﻟﺘﻠﺴـــﻜﻮﺑﺎت اﻷرﺿـــﻴﺔ ﻷن ﺘﻬﺎ ﺣﺴﺎﺳـﻴ ﻟـﻢ ﺗﻜـﻦ اﻟﻜﺎﻓ ﻴـﺔ ﻻﻛﺘﺸـﺎف ﻧﺠﻮﻣ ﻬﺎ وﻟﻜﻦ ﺑﻔﻀـﻞ ﻛـﺎﻣ ا اﻻﺳـﺘﻄﻼع ا ﺘﻘﺪﻣﺔ ﰲ ﺗﻠﺴﻜﻮب ﻫﺎﺑﻞ ﺗﻤﻜﻨﺎ ﻣﻦ اﻟﺘﺄﻛﺪ ﻣﻦ أﻧﻪ ﻻ ﻳﻮﺟﺪ ﳾء ﻫﻨﺎك وﻛﺎن اﻛﺘﺸـﺎف ﻫﺬه اﻟﺴـﺤﺎﺑﺔ ﺎً ﻣﻔﺎﺟﺌـ وأﺿـﺎﻓﺖ راﺷـﻴﻞ ﺑﻴﺎﺗﻮن ﻣﻦ ﻣﻌﻬﺪ ﻋﻠﻮم ﺗﻠﺴﻜﻮﺑﺎت اﻟﻔﻀﺎء و ﻋﻀﻮ ﰲ ﻓﺮﻳﻖ اﻟﺒﺤـﺚ :" ﻳﻌﺘﻘـﺪ أن ﻫـﺬه اﻟﺴﺤﺐ اﻟﺒﺪ اﺋﻴﺔ ا ﺤﺪودة ﺑﺈﻋﺎدة اﻟﺘﺄﻳﻦ ﻫﻲ تﻫﺎﻻ ﻣﻦ ا ﺎدة ا ﻈﻠﻤـﺔ ﻟـﻢ ﺗـﺘﻤﻜﻦ ﻣـ ﻦ ﻗﺪر ﺟﻤﻊ ﻛﺎفٍ ﻣﻦ اﻟﻐﺎز ﻟﺘﺸـﻜﻴﻞ اﻟﻨﺠـﻮم وﺗﻤﺜﻞ ﻧﺎﻓﺬة ﻟﺪراﺳﺔ ا ﺮاﺣـﻞ ا ﺒ ﻜـﺮة ﻣـﻦ ﺗﺸــﻜﻞ ا ﺠــﺮات و ﺗﺸــ اﻟﺴـﺤﺎﺑﺔ -9 إﱃ اﺣﺘﻤﺎل وﺟﻮد اﻟﻌﺪﻳﺪ ﺒﻨﻰ اﻟ ﻣﻦ اﻷﺧﺮى اﻟﺘﻲ ﺗ ﻬﻴﻤﻦ ﻋﻠﻴﻬﺎ ا ﺎدة ا ﻈﻠﻤﺔ أي ﻣﺠﺮات ﻏ ﻣﺸﻜﻠﺔ ﻟﻠﻨﺠﻮم وﻳﻘﺪم ﻫﺬا اﻻﻛ ﺘﺸﺎف رؤى ﺣﻮل ﻣﻜﻮﻧﺎت اﻟﻜﻮن ا ﻈﻠﻤﺔ اﻟﺘﻲ ﻳ ﺼـﻌﺐ دراﺳﺘﻬﺎ ﻋﱪ اﻷرﺻﺎد اﻟﺘﻘﻠﻴﺪﻳﺔ اﻟﺘﻲ ﺗﺮﻛـﺰ اﻷﺟﺮام ﻋﲆ ا ﻀﻴﺌﺔ ﻣﺜﻞ اﻟﻨﺠﻮم وا ﺠﺮات . - ﻣﺎﺭﺱ ﺃﺑﺮﻳﻞ 2 0 2 6 ﺗﻈﻬــــﺮ ﻫـــــﺬﻩ اﻟﺼـــــﻮرة ــــﺔ اﻟﺪﻗـــــﺔ ﻋﺎﻟ ﻣﻮﻗـــــﻊ اﻟﺴــــﺤﺎ ﺔ -9. اﻟﻠــــﻮن اﻷرﺟــــﻮاﻧﻲ اﻟﻤﻨﺘﺸــــﺮ ﻤﺜــــﻞ ـــــــــ ﺑ ﺎﻧـــــــــﺎت رادﻳﻮ ﺔ ﻣـــــــــﺄﺧﻮذة ﻣـــــــــﻦ اﻟﻤﺼـــــــــﻔﻮﻓﺔ اﻟﻜﺒـ ة ﺟـﺪ اً ﺗﻜﺸـﻒﻋـﻦ وﺟـﻮد اﻟﺴـﺤﺎ ﺔ واﻟـ . اﻟــــــﺪاﺋﺮة اﻟﻤﻨﻘﻄــــــﺔ ﺗﺸــــــ إﻟــــــﻰذروة اﻻﻧ ﻌــــــﺎث رﻛــــــ اﻟﺮادﻳــــــﻮيوﻫــــــﻲ اﻟﻤﻨﻄﻘـــــــﺔ اﻟــــــ ﺰﻓ ﻴﻬـــــــﺎ ـﺎﺣﺜﻮن ﺑﺤــﺜﻬﻢ ﻋــﻦ اﻟﻨﺠـﻮم اﻟ . أﻇﻬــﺮ اﻷرﺻــﺎد اﻟﻼﺣﻘﺔ ﺑﻮاﺳﻄﺔ ﺎﻣ ا اﻻﺳﺘﻄﻼع اﻟﻤﺘﻘﺪﻣـﺔ اﻟﺘﺎ ﻌــــﺔ ﻟﺘﻠﺴــــ ﻮب ﻫﺎﺑــــﻞ اﻟﺘــــﺎﺑﻊ ﻟﻮ ﺎﻟــــﺔ ﻧﺎﺳــــﺎ ـــــــﺔ وو ﺎﻟـــــــﺔ اﻟﻔﻀـــــــﺎء اﻷوروﺑ ﻋـــــــﺪم وﺟـــــــ ﻮد أي ﻧﺠﻮم داﺧﻞ اﻟﺴﺤﺎ ﺔ . أﻣﺎ اﻷﺟ ﺮام اﻟﻘﻠ ﻠﺔ اﻟ ﺗﻈﻬـــﺮﺿـــﻤﻦ ﺣــــﺪ ﻓ ودﻫﺎ ــــﺔ ﻬـــﻲﻣﺠـــﺮاتﺧﻠﻔ . ﻗﺒـــــــﻞ أرﺻــــــــﺎد ﺗﻠﺴــــــــ ﻮ ب ﻫﺎﺑـــــــﻞ ــــــــﺎن اﻟﻌﻠﻤــــــــﺎء ﻤﻜــــــﻨﻬﻢ اﻟــــــ ـ ــــــﺄن اﻟﺴــــــﺤﺎ ﺔ ﺠﺪال 9- ﻗــــــﺪ ــــــﻮن ﺗ ﻣﺠﺮة ﻗﺰﻣﺔ ﺧﺎﻓﺘﮫ ﺣ ﺚ ﻻ ﻤﻜﻦ رؤ ﺔ ﻧﺠﻮﻣﻬﺎ ﺎﺳـــــــــــــﺘﺨﺪام اﻟﺘﻠﺴـــــــــــــ ﻮ ﺎت اﻷرﺿـــــــــــــ ﺔ ﺴــــــــــــــ ﺐ ــــــﺔ اﻟــــــ ﻣﺤﺪود ـ ﺤﺴﺎﺳ ﺔ ﺗ. ــــــﺎﻣ ا ﻈﻬــــــﺮﺑ ﺎﻧــــــﺎت اﻻﺳﺘﻄﻼع اﻟﻤﺘﻘﺪﻣﺔ ﻟ ﺘﻠﺴـ ﻮب ﻫﺎﺑـﻞ أن ﻫـﺬﻩ اﻟﻤﺠﺮة اﻟﻔﺎﺷﻠﺔ ﻻ ﺗﺤﺘﻮيﻋﻠﻰ أي ﻧﺠﻮم . [NASA, ESA. G.Anand (STScI), and A. Benitez-Llambay (Univ. of Milan-Bicocca); Image processing: J. DePasquale (STScI)