Free Astronomy Magazine March-April 2025 ARABIC VERSION

49 245 th meeting of the American As- tronomicalSocietyinNationalHar- bor, Maryland. “Even as a star dies, its light en- dures—echoing across the cosmos. It’s been an extraordinary three years since we launched NASA’s James Webb Space Telescope. Every image,everydiscovery,showsapor- trait not only of the majesty of the universe but the power of the NASA team and the promise of interna- tionalpartnerships.Thisground- breaking mission, NASA’s largest in- ternational space science collabora- tion, is a true testament to NASA’s ingenuity, teamwork, and pursuit of excellence,” said NASA Administra- tor Bill Nelson. “What a privilege it has been to oversee this monumen- taleffort,shapedbythetirelessded- icationofthousandsofscientistsand engineers around the globe. This latestimagebeautifullycapturesthe lasting legacy of Webb—a keyhole intothepastandamissionthatwill inspire generations to come.” The imagesfromWebb’sNIRCam(Near- Infrared Camera) highlight a phe- nomenon known as a light echo. A lightechoiscreatedwhenastarex- plodesorerupts,flashinglightinto surrounding clumps of dust and causingthemtoshineinanever-ex- pandingpattern.Lightechoesatvis- iblewavelengths(suchasthoseseen around the star V838 Monocerotis) areduetolightreflectingoffofin- terstellar material. In contrast, light echoesatinfraredwavelengthsare causedwhenthedustiswarmedby energeticradiationandthenglows. The researchers targeted a light echo that had previously been ob- served by NASA’s retired Spitzer SpaceTelescope.Itisoneofdozens of light echoes seen near the Cas- siopeia A supernova remnant – the remains of the star that exploded. Thelightechoiscomingfromunre- lated material that is behind Cas- siopeia A, not material that was ejected when the star exploded. ﺴــــﻠﻂ ـــــﺪﻳﻮ اﻟﻤﺼــــﻮر ﺎﺳـــــﺘﺨﺪام ﺑ ﺎﻧــــﺎت ﻣـــــﻦ ﺗﻠﺴـــــ ﻮب ﻫـــــﺬا اﻟﻔ ﺟ ﻤﺲو ﺐ اﻟﻔﻀﺎﺋﻲ اﻟﺘﺎﺑﻊ ﻟﻮ ﺎﻟﺔ ﻧﺎﺳﺎ ا ﻟﻀﻮء ﻋﻠﻰ ﺗﻄـﻮرﺻـﺪ ــﺎ اﻟﻤﺴــﺘﻌﺮاﻷﻋﻈـــﻢ اﻟﻀــﻮء ﻓــﻲﻣﺤـــ ﻂ ﻘﺎ ذات اﻟﻜﺮﺳــﻲ . أ ﻨﺸـــﺄ ﺻــــﺪ ــــﻢ أو ﺜــــﻮر اﻟﻀــــﻮء ﻋﻨــــﺪﻣﺎ ﻨﻔﺠــــﺮﻧ ﻣﻤــــﺎ ﻨ ﻌــــﺚ ﻣﻨــــﮫ ﺿــــﻮء اﻟﻨﺠــــــﻮم اﻟﻤﺤ ﻄــــــﺔ و ﺘﺴــــــ ﺐ ﻓـــــــﻲ ــــــﺎرﺑــــــ ﺧﺎﻓــــــﺖ ﻓــــــﻲﻛﺘــــــﻞ اﻟﻐ ـﺪًا ﻟﻤﻌﺎﻧﻬـﺎ ﻓـﻲ ﻧﻤـﻂﻻ ﺘﻮﺳـﻊ أ . ﻻ ﺗُﻈﻬـﺮ دﻗـﺔ ﺗﻠﺴـ ﻮبﺟـ ﻤﺲ ــﺐ اﻟﺮاﺋﻌــﺔ ﺗﻔﺎﺻــﻴﻞ ﻻ و ﺗﺼــﺪق داﺧــﻞ أﺻــﺪاء اﻟﻀــﻮء ﻫــﺬﻩ ﻓﺤﺴـــﺐ ﺑـــﻞ ﻛـــﺬﻟﻚ ﺗُﻈﻬـــﺮأ ﻀًـــﺎ ﺗ ﻮﺳـــﻌﻬﺎ ﻋﻠـــﻰ ﻣـــﺪار ﻀـــﻌﺔ أﺳـــﺎﺑﻴﻊ ﻓﻘـــﻂ وﻫـــــــﻲ ـــــــﺔ ﻗﺼـــــــ ة ﺸـــــــ ﻞ ﻣﻠﺤـــــــﻮظ ﻧﻈـــــــﺮ ﻓـــــــ ة زﻣﻨ اً ﻷن ﻣﻌﻈـــــــﻢ اﻷﻫﺪاف اﻟ ﻮﻧ ﺔ ﺗﻈﻞ دون ﺗﻐﻴ ﻋﻠﻰﻣﺪار ﻋﻤﺮاﻹﻧﺴﺎن . .[NASA,ESA,CSA,STScI,JacobJencson(Cal- tech/IPAC), Joseph DePasquale (STScI)] ﰲ اﻻﺟﺘﻤﺎع اﻟﺨﺎﻣﺲ واﻷرﺑﻌ ﺑﻌـﺪ ا ﺎﺋـﺔ ﻟﻠﺠﻤﻌﻴﺔ اﻟﻔﻠﻜﻴﺔ اﻷﻣﺮﻳﻜﻴـﺔ ﰲ ﻧﺎﺷـﻴﻮﻧﺎل ﻫﺎرﺑﻮر ﺑﻮﻻﻳﺔ ﻣ ﺎرﻳﻼﻧﺪ . ﺣﺘﻰ ﻋﻨﺪﻣﺎ ﻳﻤﻮت اﻟﻨﺠﻢ ﻳﻈﻞ ﺿﻮءه ﺑﺎﻗﻴـﺎً ﻳﱰدد ﺻﺪاه ﻋﱪ اﻟﻜﻮن . ﻟﻘـﺪ ﻣـﺮت ﺛـﻼث ﺳﻨﻮات ﻏ ﻋﺎدﻳﺔ ﻣﻨﺬ أن أﻃﻠﻘﻨﺎ ﺗﻠﺴﻜﻮب ﺟﻴﻤﺲ وﻳﺐ اﻟﻔﻀﺎﺋﻲ اﻟﺘﺎﺑﻊ ﻟ ﻮﻛﺎﻟﺔ ﻧﺎﺳﺎ . ﻛﻞ ﺻﻮرة، وﻛﻞ اﻛﺘﺸﺎف ﻳُﻈﻬِﺮ ﺻﻮ رة ﻟﻴﺲ ﻓﻘﻂ ﻟﻌﻈﻤﺔ اﻟﻜﻮن وﻟﻜﻦ أﻳﻀ ﺎً ﻟﻘﻮة ﻓﺮﻳﻖ وﻛﺎﻟﺔ ﻧﺎﺳﺎ وﻣﺎ ﺗﻌﺪ ﺑﻪ اﻟﴩا ﻛﺎت اﻟﺪوﻟﻴﺔ . ﻫ إن ﺬه ا ﻬﻤﺔ اﻟﺮاﺋﺪة ﻫﻲ أﻛﱪ ﺗﻌﺎون دوﱄ ﰲ ﻣﺠﺎل ﻋﻠﻮم اﻟﻔﻀﺎء ﻟﻮﻛﺎﻟﺔ ﻧﺎﺳـﺎ ﻫـﻲ و ﺷﻬﺎدة ﺣﻘﻴﻘﻴﺔ ﻋﲆ ﺑﺮاﻋﺔ ﻧﺎﺳـﺎ وﻋ ﻤﻠﻬـﺎ اﻟﺠﻤﺎﻋﻲ وﺳـﻌﻴﻬﺎ إﱃ اﻟﺘﻤﻴـﺰ . ﻗـﺎل ﻣـﺪﻳﺮ ﻧﺎﺳﺎ ﺑﻴﻞ ﻧﻴﻠﺴﻮن :" ﻟﻘﺪ ﻛـﺎن ﻣـﻦ دواﻋـﻲ ﴎ وري اﻹﴍاف ﻋﲆ ﻫﺬا اﻟﺠﻬـﺪ اﻟﻀـﺨﻢ اﻟﺬي ﺗﺸﻜﻞ ﺑﻔﻀـﻞ اﻟﻌﻤـﻞ اﻟـﺪؤوب ﻵﻻف اﻟﻌﻠﻤﺎء وا ﻬﻨﺪﺳ ﰲ ﺟﻤﻴﻊ أﻧﺤﺎء اﻟﻌـﺎﻟﻢ . ﻫﺬه اﻟﺼﻮرة اﻷﺧ ة ﺗﻠﺘﻘﻂ ﺑﺸـﻜﻞ ﺟﻤﻴـﻞ اﻹرث اﻟﺪاﺋﻢ ﻟ ﺘﻠﺴﻜﻮب وﻳـﺐ وﻧﻈـﺮه ﻣـﻦ ﺛﻘﺐ ا ﻔﺘﺎح اﱃ ا ﺎﴈ وا ﻬﻤﺔ اﻟﺘﻲ ﺳﺘﻠﻬﻢ اﻷﺟﻴﺎل اﻟﻘﺎدﻣﺔ . ﺗﺴﻠﻂ اﻟﺼﻮر ﻣﻦ ﻛـﺎﻣ ا ﺗﺤ ﺗﻠﺴﻜﻮب اﻷﺷﻌﺔ ﺗﺤﺖ اﻟﺤﻤﺮاء اﻟﻘﺮﻳﺒﺔ ﻋﲆ ﺗﻠﺴﻜﻮب وﻳﺐ اﻟﻀﻮء ﻋﲆ ﻇﺎﻫﺮة ﺗُﻌﺮف ﺑﺎﺳﻢ ﺻﺪى اﻟﻀﻮء . ﻳﻨﺸﺄ ﺻﺪى اﻟﻀﻮء ﻋﻨـﺪﻣﺎ ﻳﻨﻔﺠـﺮ ﻧﺠﻢ، ﻓﻴﻮﻣﺾ اﻟﻀﻮء ﰲ ﻛﺘﻞ اﻟﻐﺒﺎر ا ﺤﻴﻄﺔ وﻳﺘﺴﺒﺐ ﰲ ﺗﺄﻟﻘﻬﺎ ﰲ ﻧﻤﻂ ﻻ ﻳﺘﻮﺳﻊ أﺑﺪ .اً ﺗﺮﺟﻊ أﺻـﺪاء اﻟﻀـﻮء ﰲ اﻷﻃـﻮال ا ﻮﺟﻴـﺔ ا ﺮﺋﻴﺔ ) ﻣﺜﻞ ﺗﻠﻚ اﻟﺘ ﻲ ﻧﺮاﻫـﺎ ﺣـﻮل اﻟـﻨﺠﻢ V838 ﻣﻮﻧﻮﺳ وﺗﻴﺲ ( إﱃ اﻟﻀﻮء ا ﻨﻌﻜﺲ ﻋﻦ ﻣﺎدة ﺑ اﻟﻨﺠﻮم . وﻋـﲆ اﻟﻨﻘـﻴﺾ ﻣـﻦ ذﻟـﻚ، ﺗﺤـﺪث أﺻـﺪاء اﻟﻀـﻮء ﰲ اﻷﻃـﻮال ا ﻮﺟﻴﺔ ﺗﺤﺖ اﻟﺤﻤﺮاء ﻋﻨﺪﻣﺎ ﻳﺤﻴﻂ اﻟﻐﺒـﺎر ﺑﺎﻹﺷﻌﺎع اﻟﻨﺸﻂ واﻟﺘﻮﻫﺠﺎت . ﻟﻘﺪ اﺳﺘﻬﺪف اﻟﺒﺎﺣﺜﻮن ﺻﺪى اﻟﻀﻮء اﻟـﺬي ﺳﺒﻖ أن رﺻﺪه ﺗﻠﺴﻜﻮب ﺳﺒﻴﺘﺰر اﻟﻔﻀﺎﺋﻲ ا ﺘﻘﺎﻋﺪ اﻟﺘﺎﺑﻊ ﻟﻮﻛﺎﻟﺔ ﻧﺎﺳﺎ . إﻧﻪ واﺣﺪ ﻣـﻦ ﻋﴩـات أﺻـﺪاء اﻟﻀـﻮء اﻟﺘـﻲ ﺷـﻮﻫﺪت ﺑﺎﻟﻘﺮب ﻣﻦ ﺑﻘﺎﻳﺎ ﻣﺴﺘﻌﺮ أﻋﻈﻢ ﻛﺎﺳﻴﻮﺑﻴﺎ أ - ﺑﻘﺎﻳﺎ اﻟﻨﺠﻢ اﻟﺬي اﻧﻔﺠﺮ . إن ﺻﺪى اﻟﻀﻮء ﻳﺄﺗﻲ ﻣﻦ ﻣﺎدة ﻏ ذات ﺻﻠﺔ ﻣﻮﺟﻮدة ﺧﻠﻒ ﻛﺎﺳﻴﻮﺑﻴﺎ أ، وﻟـﻴﺲ ﻣـﻦ ﻣـﺎدة ﺗـﻢ ﻗـﺬﻓﻬﺎ ﻋﻨﺪﻣﺎ اﻧﻔﺠﺮ اﻟﻨﺠﻢ . إن أﻛﺜﺮ اﻟﺴﻤﺎت وﺿﻮﺣً ﺎ ﰲ ﺻﻮر ﺗﻠﺴﻜﻮب وﻳﺐ ﻫﻲ ﺻﻔﺎﺋﺢ ﻣﺘﻤﺎﺳﻜﺔ ﺑﺈﺣﻜﺎم . ﺗُﻈﻬﺮ ﻫﺬه اﻟﺨﻴﻮط ﻫﻴﺎﻛﻞ ﻋﲆ ﻧﻄﺎﻗـﺎت ﺻـﻐ ة ﺑﺸـﻜﻞ ﻣﻠﺤـﻮظ ﺗﺒﻠـﻎ ﺣـﻮاﱄ 400 وﺣـﺪة ﻓﻠﻜﻴـﺔ أو أﻗـﻞ ﻣـﻦ ﻣﺎﺋــﺔ ﺳـﻨﺔ ﺿـﻮﺋﻴﺔ . ) اﻟﻮﺣﺪة اﻟﻔﻠﻜﻴﺔ ﻫﻲ ﻣﺘﻮﺳﻂ ا ﺴﺎﻓﺔ ﺑـ اﻷرض واﻟﺸﻤﺲ ﻳﺒﻠﻎ ﻗﻄﺮ ﻣﺪار ﻧﺒﺘﻮن 60 وﺣﺪة ﻓﻠﻜﻴﺔ .( ﻗﺎل ﺑﻴﻚ " : ﻟﻢ ﻧﻜﻦ ﻧﻌﺮف أن اﻟﻮﺳﻂ ﺑ اﻟﻨﺠﻮم ﻳﺤﺘﻮي ﻋﲆ ﻫﻴﺎﻛﻞ ﻋﲆ ﻫﺬا اﻟﻨﻄﺎق اﻟﺼﻐ و ﺑﻞ ﺗﺸﺒﻪ اﻟﺼﻔﺎﺋﺢ ." 49 ﺃﺑﺮﻳﻞ - ﻣﺎﺭﺱ 2 0 2 5