Free Astronomy Magazine September-October 2025 ARABIC VERSION

SEPTEMBER-OCTOBER2025 confirmedthattheintraclusterlight canbeareliabletracerofdarkmat- ter, even in a highly dynamic envi- ronment like the Bullet Cluster,” Cha said. If these stars are notbound to galaxies, but to the clus- ter’s dark matter, it might become easier to pin down more specifics about the invisible matter. Viewed as a whole, the researchers’ new measurements significantly re- fine what we know about how massis spread throughout the Bullet Cluster. The galaxy cluster on the left has an asymmetric, elongated area of mass along the left edge of the blue region, which is a clue pointing to previous mergers in that cluster. Dark matter does not emit, reflect,orabsorblight,andthe team’s findings indicate that dark matter shows no signs of significant self-interaction. If dark matter did self-interactinWebb’sobservations, the team would see an offset be- tween the galaxies and their respec- tive dark matter. “As the galaxy clusters collided, their gas was dragged out and left behind,whichtheX-raysconfirm,” Finner said. Webb’s observations showthatdarkmatterstilllinesup with the galaxies — and was not dragged away. Although earlier measurements with other telescopes also identified invisible mass in addition to the massinthegalaxies,itwasstillpos- siblethatthedarkmattercouldin- teractwithitselftosomedegree. These new observations place stronger limits on the behavior of dark matter particles. The strange new clumps and elon- gated line of mass the team identi- fied may mean that the BulletCluster was produced by more than one collision of galaxy clusters bil- lions of years ago. The larger clus- ter, which now sits on the left,might have suffered a minor colli- sion before it rammed through the galaxy cluster now at right. Thesame larger cluster may also have experienced a violent interaction afterward, causing an additional shake up of its contents. “A more complicated scenario would lead toa huge asymmetric elongation like we see onthe left,” Jee said.  إذا ﻟﻢ ﺗﻜﻦ ﻫﺬه اﻟﻨﺠﻮم ﻣﺮﺗﺒﻄ ﺔ ﺑﺎ ﺠﺮات ﺑﻞ ﺑﺎ ﺎدة ا ﻈﻠﻤـﺔ ﻟﻠﻌﻨﻘـﻮد ﻓﻘـﺪ ﻳﺼـﺒﺢ ﻣـﻦ اﻷﺳﻬﻞ ﺗﺤﺪﻳﺪ ﺗﻔﺎﺻﻴﻞ أﻛﺜﺮ ﺣﻮل ا ﺎد ة ﻏـ ا ﺮﺋﻴﺔ . ﺑﺎﻟﻨﻈﺮ إﻟﻴﻬﺎ ﻛﻜﻞ ﺗﺤﺴـ ﻦ ﻗﻴﺎﺳـﺎت اﻟﺒﺎﺣﺜ اﻟﺠﺪﻳﺪة ﺑﺸﻜﻞ ﻛﺒ ﻣﺎ ﻧﻌﺮﻓﻪ ﻋـﻦ ﻛﻴﻔﻴﺔ اﻧﺘﺸﺎر اﻟﻜﺘﻠﺔ ﰲ ﺟﻤﻴﻊ أﻧﺤﺎء ﻋﻨﻘـﻮد اﻟﻄﻠﻘﺔ . ﻳﺘﻤﻴﺰ ﻋﻨﻘﻮد ا ﺠﺮات ﻋـﲆ اﻟﻴﺴـﺎر ﺑﻤﻨﻄﻘﺔ ﻛﺘﻠﺔ ﻏ ﻣﺘﻤﺎﺛﻠﺔ وﻣﻤﺘﺪة ل ﻋﲆ ﻃﻮ اﻟﺤﺎﻓﺔ اﻟﻴﴪ ى ﻟﻠﻤﻨﻄﻘﺔ اﻟﺰرﻗﺎء وﻫﻮ دﻟﻴـﻞ ﻳﺸ إﱃ اﻧﺪﻣ ﺎﺟﺎت ﺳﺎﺑﻘﺔ ﰲ ذﻟﻚ اﻟﻌﻨﻘﻮد . ﻻ ﺗﺼﺪر ا ﺎدة ا ﻈﻠﻤﺔ اﻟﻀﻮء وﻻ ﺗﻌﻜﺴﻪ وﻻ ﺗﻤﺘﺼﻪ وﺗﺸـ ﻧﺘـﺎﺋﺞ اﻟﻔ ﺮﻳـﻖ إﱃ أن ا ـﺎدة ا ﻈﻠﻤﺔ ﻻ ﺗ ﻈﻬﺮ أي ﻋﻼﻣﺎت ﻋﲆ ﺗﻔﺎﻋﻞ ذاﺗﻲ . ﻛﺒ إذا ﺗﻔﺎﻋﻠﺖ ا ﺎدة ا ﻈﻠﻤﺔ ذاﺗﻴﺎً أرﺻﺎد ﰲ ﺗﻠﺴﻜﻮب وﻳﺐ ﻓﺴ ى اﻟﻔﺮﻳـﻖ إزاﺣـﺔ ﺑـ ا ﺠﺮات وﻣﺎدﺗﻬﺎ ا ﻈﻠﻤﺔ . ﺎل ﻓﻴﻨﺮ ﻗ " : ﻋﻨﺪﻣﺎ اﺻﻄﺪﻣﺖ ﻋﻨﺎﻗﻴﺪ ا ﺠﺮات ﺳُﺤﺐ ﻏﺎزﻫﺎ وﺗﺮك ﺧﻠﻔﻬﺎ وﻫـﻮ ﻣـﺎ ﺗﺆﻛـﺪه اﻷﺷﻌ ﺔ اﻟﺴﻴﻨﻴﺔ ." ﺗﻈﻬـﺮ أرﺻـﺎد ﺗﻠﺴـﻜﻮب وﻳﺐ أن ا ـﺎدة ا ﻈﻠﻤـﺔ ﻻ ﺗـﺰال ﺑﺎﻗﻴـﺔ ﻣـﻊ ا ﺠﺮات وﻟﻢ ﺗﺴﺤﺐ ﺑﻌﻴﺪ .اً ﻋ ـﲆ اﻟ ـﺮﻏﻢ ﻣ ـﻦ أن اﻟﻘﻴﺎﺳ ـﺎت اﻟﺴ ـﺎﺑﻘﺔ ﺑﺎﺳﺘﺨﺪام ﺗ ﻠﺴﻜﻮﺑﺎت أﺧـﺮى ﺣـﺪدت أﻳﻀـ ﺎً ﻛﺘﻠﺔ ﻏ ﻣﺮﺋﻴﺔ ﺑﺎﻹﺿﺎﻓﺔ إﱃ اﻟﻜﺘﻠﺔ ا ﻮﺟﻮدة ﰲ ا ﺠﺮات إﻻ أﻧﻪ ﻛﺎن ﻻ ﻳﺰال ﻣﻦ ا ﻤﻜـﻦ أن ﺗﺘﻔﺎﻋﻞ ا ﺎدة ا ﻈﻠﻤﺔ ﻣﻊ ﻧﻔﺴﻬﺎ إﱃ ﺣﺪ ﻣـ . ﺎ ﺗﻀﻊ ﻫﺬه اﻷرﺻﺎد اﻟﺠﺪﻳﺪة ﺣﺪود اً أﻗﻮى ﻋﲆ ﺳﻠﻮك ﺟﺴﻴﻤﺎت ا ﺎدة ا ﻈﻠﻤﺔ . ﻗﺪ ﺗﻌﻨﻲ اﻟﺘﻜﺘﻼت اﻟﺠﺪﻳـﺪة اﻟﻐﺮﻳﺒـﺔ وﺧـﻂ اﻟﻜﺘﻠﺔ اﻟﻄﻮﻳﻞ اﻟﺬي ﺣﺪده اﻟﻔﺮﻳﻖ أن ﻋﻨﻘـﻮد اﻟﻄﻠﻘﺔ ﻗﺪ ﻧﺘﺞ ﻋﻦ أﻛﺜﺮ ﻣﻦ ﺗﺼﺎدم ﻟﻌﻨﺎﻗﻴـﺪ ا ﺠﺮات ﻣﻨﺬ ﻣﻠﻴﺎرات ا ﻟﺴﻨ . رﺑﻤﺎ ﻳﻜﻮن اﻟﻌﻨﻘﻮد اﻷﻛﱪ ا ﻮﺟـﻮد اﻵن ﻋـﲆ اﻟﻴﺴﺎر ﻗﺪ ﺗﻌﺮضﻻﺻﻄﺪام ﻃﻔﻴـﻒ ﻗﺒـﻞ أن ﻳﺼﻄﺪم ﺑﺎﻟﻌﻨﺎﻗﻴﺪ ا ﺠﺮﻳﺔ ا ﻮﺟﻮدة اﻵن ﻋﲆ اﻟﻴﻤ . رﺑﻤﺎ ﻳﻜﻮن اﻟﻌﻨﻘﻮد اﻷﻛﱪ ﻧﻔﺴﻪ ﻗـﺪ ﺗﻌﺮض أﻳﻀ ﺎً ﻟﺘﻔﺎﻋﻞ ﻋﻨﻴـﻒ ﺑﻌـﺪ ذﻟـﻚ ﻣﻤـﺎ ﺗﺴﺒﺐ ﰲ ﻫﺰة إﺿﺎﻓﻴﺔ ﺤﺘﻮﻳﺎﺗﻪ . ﻗﺎل ﺟﻲ " : ﺳﻴﻨﺎرﻳﻮ أﻛﺜﺮ ﺗﻌﻘﻴﺪ اً ﻣـﻦ ﺷـﺄﻧﻪ أن ﻳﺆدي إﱃ اﺳﺘﻄﺎﻟﺔ ﻏ ﻣﺘﻤﺎﺛﻠـﺔ ﺿـﺨﻤﺔ ﻛﻤﺎ ﻧﺮى ﻋﲆ اﻟﻴﺴﺎر إن ". ﻫﺬا ﻳﺸ إﱃ ﺗﺎرﻳﺦ ﺗﺼﺎدﻣﺎت ﻣﻌﻘﺪة أﺛﺮت ﻋﲆ ﺗﺸﻜﻴﻞ اﻟﻌﻨﻘـﻮد وﺗﻮزﻳﻌـﻪ اﻟﺤـ ﺎﱄ ﻟﻠﻤـﺎدة ا ﻈﻠﻤ ـﺔ وا ـﺎدة اﻟﻌﺎدﻳﺔ . ﺗُﻈﻬﺮ ﻫﺬه اﻻﺳﺘﻄﺎﻟﺔ أن اﻟﻌﻨﻘﻮد ﻟﻢ ﻳﺘﺸﻜﻞ ﺑﺒﺴﺎﻃﺔ ﻣﻦ ﺧـﻼل ﻋﻤﻠﻴـ ﺔ اﻧـﺪﻣﺎج واﺣﺪة ﺑﻞ ﻣﺮ ﺑﻌﺪة ﻣﺮاﺣـﻞ ﻣـﻦ اﻟﺘﻔـﺎﻋﻼت اﻟﻌﻨﻴﻔﺔ . ﻗﺪ ﻳﻜﻮن ﻫﺬا اﻻﺻـﻄﺪام ا ﻷوﱄ ﻗـﺪ أﺣﺪث اﺿـﻄﺮاﺑﺎً و ﰲ ﺑﻨﻴﺘـﻪ ﺑﻌـﺪ ذﻟـﻚ رﺑﻤـﺎ ﺗﻌﺮض اﻟﻌﻨ ﻘﻮد اﻷﻛﱪ ﻧﻔﺴﻪ ﻟﺘﻔﺎﻋﻞ ﻋﻨﻴـﻒ ﺮ آﺧ ﻣﻤﺎ أﺿﺎف ا ﺰﻳﺪ ﻣﻦ اﻟﻬـﺰة ﺤﺘﻮﻳﺎﺗـﻪ وﺳﺎﻫﻢ ﰲ ﻫﺬه اﻻﺳﺘﻄﺎﻟﺔ اﻟﻮاﺿﺤﺔ . ـــــ ﺳﺒﺘﻤﺒﺮ - ﺃﻛﺘﻮﺑﺮ 2 0 2 5