Free Astronomy Magazine January-February 2025 ARABIC VERSION

Best test yet of how gravity behaves at cosmic scales by NOIRLab Josie Fenske ravityhasshapedourcos- mos. Its attractive influenceturned tiny variations in the amountofmatterpresentinthe earlyUniverseintothesprawling strandsofgalaxiesweseetoday.A newstudyusingthefirstyearof datafromtheDarkEnergySpectro- scopicInstrument(DESI)hastraced howthiscosmicstructuregrewover the past 11 billion years, providing the most precise test to date of how gravity behaves at very large scales. DESI is a state-of-the-art instrument that can capture light from 5000 galaxies simultaneously. It was con- structed, and is operated, with funding from the DOE Office of Science.DESIismountedonthe U.S.NationalScienceFoundation Nicholas U. Mayall 4-meter Tele- scope at Kitt Peak National Obser- vatory, a Program of NSF NOIRLab. The program is now in its fourth of five years surveying the sky and is set to observe roughly 40 million galaxiesandquasarsbythetimethe project ends. TheDESIprojectisaninternational collaborationofmorethan900re- JANUARY-FEBRUARY2025 G ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 48 أﻓﻀﻞ ا ﺧﺘ ﺎر اﻵن ﺣ ﻟﺴﻠﻮك ـاﻟ ﺠﺎذﺑ ﺔ ﻋﻠﻰاﻟﻤﻘﺎﻳ ﺲ اﻟ ﻮﻧ ﺔ : ﻘﻠﻢ ﺟﻮزيﻓ ﻨﺴﻜﻲ - ﻣﺨﺘ ﻧﻮﻳﺮﻻب ﻟﻘـﺪ ﺷﻜﻠﺖ اﻟﺠﺎذﺑﻴﺔ اﻟﻜﻮن و ﺣﻮل ﺗﺄﺛ ﻫﺎ ذﺎ اﻟﺠ ب اﻻﺧﺘﻼﻓﺎت اﻟﻄﻔﻴﻔﺔ ﰲ ﻛﻤﻴﺔ ا ﺎدة ا ﻮﺟﻮدة ﰲ اﻟﻜﻮن ا ﺒﻜﺮ إﱃ ﺧﻴﻮط ﻣﱰاﻣﻴﺔ اﻷﻃﺮاف ﻣﻦ ا ﺠﺮات اﻟﺘﻲ ﻧﺮاﻫﺎ اﻟﻴﻮم . وﻗﺪ ﺗﺘﺒﻌﺖ دراﺳﺔ ﺟﺪﻳﺪة ﺑﺎﺳـﺘﺨﺪام أول ﻋـﺎم ﻣﻦ اﻟﺒﻴﺎﻧﺎت ﻣﻦ ﻣﻄﻴﺎف اﻟﻄﺎﻗـﺔ ا ﻈﻠﻤـﺔ ) DESI ( ﻛﻴﻒ ﻧﻤﺎ ﻫﺬا اﻟﻬﻴﻜﻞ اﻟﻜﻮﻧﻲ ﺧﻼل 11 ﻣﻠﻴﺎر ﺳﻨﺔ ا ﺎﺿﻴﺔ ﻣﻤﺎ ﻳﻮﻓﺮ اﻻﺧﺘﺒـﺎر اﻷﻛﺜﺮ دﻗﺔ ﺣﺘﻰ اﻵن ﻟﺴﻠﻮك اﻟﺠﺎذﺑﻴﺔ ﻋـﲆ ــ ﻧﻄﺎﻗـﺎت ﻛﺒـ ة ﺟـﺪ إن . اً ﺟﻬـﺎز ﻣﻄﻴـﺎف اﻟﻄﺎﻗﺔ ا ﻈﻠﻤﺔ ﻫﻮ ﺟﻬﺎز ﻣﺘﻄـﻮر ﻳﻤﻜﻨـﻪ اﻟﺘﻘﺎط اﻟﻀﻮء ﻣـﻦ ﺧﻤﺴـﺔ أﻻف ﰲ ﻣﺠـﺮة وﻗﺖ واﺣﺪ . ﻟﻘﺪ ﺗﻢ ﺑﻨﺎؤه وﺗﺸﻐﻴﻠﻪ ﺑﺘﻤﻮﻳﻞ ﻣـﻦ ﻣﻜﺘـﺐ اﻟﻌﻠﻮم اﻟﺘﺎﺑﻊ ﻟﻮزارة اﻟﻄﺎﻗـﺔ . ﺗـﻢ ﺗﺮ ﻛﻴـﺐ ﺟﻬﺎز ﻣﻄﻴﺎف اﻟﻄﺎﻗﺔ ا ﻈﻠﻤﺔ ﻋﲆ ﺗﻠﺴﻜﻮب ﻧﻴﻜﻮﻻس ﻳﻮ ﻣﺎﻳﺎل اﻟﺒـﺎﻟﻎ ﻗﻄـﺮه 4 أﻣﺘـﺎر اﻟﺘﺎﺑﻊ ﻟﻠ ﻤﺆﺳﺴﺔ اﻟﻮﻃﻨﻴﺔ ﻟﻠﻌﻠﻮم ﰲ ﻣﺮﺻـﺪ ـ ــ ﻛﻴﺖ ﺑﻴﻚ اﻟﻮﻃﻨﻲ وﻫﻮ ﺑﺮﻧﺎﻣﺞ ﺗﺎﺑﻊ ﺨﺘـﱪ ﻧﻮﻳﺮﻻب اﻟﺘﺎﺑﻊ ﺆﺳﺴﺔ اﻟﻌﻠﻮم اﻟﻮﻃﻨﻴﺔ . اﻵن ﻳﻤﺮ اﻟﱪﻧﺎﻣﺞ ﺑﻤﺮﺣﻠﺘـﻪ اﻟﺮ اﺑﻌـﺔ ﻣـﻦ ﺧﻤﺲ ﺳﻨﻮات ﰲ ﻣﺴﺢ اﻟﺴﻤﺎء وﻣﻦ ا ﻘﺮر أن ﻳﺮاﻗﺐ ﻣـﺎ ﻳﻘـﺮب ﻣـﻦ أرﺑﻌـ ﻣﻠﻴـﻮن ا اتﺠﺮ واﻟﻜﻮازارت ﺑﺤﻠﻮل ﻧﻬﺎﻳﺔ ا ﴩوع . ﻣﴩوع ﻣﻄﻴﺎف اﻟﻄﺎﻗﺔ ا ﻈﻠﻤﺔ ﻫﻮ ﺗﻌﺎون دوﱄ ﻷﻛﺜﺮ ﻣﻦ 900 ﺑﺎﺣـﺚ ﻣـﻦ أﻛﺜـﺮ ﻣـﻦ ﺳﺒﻌ ﻣﺆﺳﺴﺔ ﺣﻮل اﻟﻌﺎﻟﻢ وﻳﺪﻳﺮه ﻣﺨﺘﱪ ـ - ﻳﻨﺎﻳﺮ ﻓﺒﺮﺍﻳﺮ 2 0 2 5