Free Astronomy Magazine September-October 2026 ARABIC VERSION

SEPTEMBER-OCTOBER2026 four spiral arms (we now know the answertobefour).Now,anotherof ESA’smissionshasfoundanewway to map the extremities of our gal- axy. “We usually model the Milky Way’souterarmsindirectlybasedon what we know of how our galaxy rotates,butdoingitthiswayleaves roomforerror,” saysBeatriceVaia of Istituto Nazionale di Astrofisica (INAF),Italy,wholedtheresearchas part of her PhD. “Instead, we did something new: we looked at the aftermath of three cosmic explo- sionsthattookplaceinfarmoredis- tantgalaxies.Theseexplosionsflung outX-raysthatechoedthroughsev- eraloftheMilkyWay’souterarms– andwemeasuredthedistancesto these echoes directly.” X-ray light was thrown out by three bright ex- plosionsknownasgamma-raybursts (GRBs).TheX-raysbouncedaround and were scattered by dust grains withintheMilkyWaygalaxy’sspiral arms,formingbrightringsthatwere then picked up by XMM- NewtonandChandra.Bystudyinghowt hese ring- shapedechoesslowlyexpanded over time, Beatrice and colleagues were able to pinpoint the distance of the scattering dust grains. As theselieincloudswithinthearmsof ourgalaxy,theteamcoulddirectly measure the distance of the arms. Besides confirming the known dis- tancetothePerseusarm,thescien- tistsfoundthattwooftheMilky Way galaxy’s arms – Outer Scutum-CentaurusArmand Outer Arm – lie up to 10% further away than we thought. WhileESA’sGaiahasrevolu- tionised our understanding oftheMilkyWaygalaxy,the distancemeasurementsavail- able so far from the tele- scopearelesspreciseforthe outer arms. Using X-rays to probe the distances to dust clouds, as XMM-Newton and Chandra did here, is highly accurate out to longer dis- tances, allowing the research team to revise the map of the outer Milky Way galaxy. “This finding is a great ex- ampleofhowESA’slong-er- standing missions – such as XMM-Newton, which launchedin1999–stillhave a hugely important role to play in exploring the Uni- verse,” says Erik Kuulkers, ESA XMM-Newton project scientist. “Now in its third decade, XMM-Newton con- tinues to return a steady stream of groundbreaking scienceoneverythingfrom the brightest-ever GRB, to stars beingshreddedbyblackholes,to X-ray snapshots of Mars. It’s even more exciting when missions team up,astheydidhere.Together,they can reveal huge amounts about the skies around us.” What we know of our home galaxy will continue to grow in coming years.Alongsideevermoredetailed data from Gaia’s fourth and fifth data releases (planned for Decem- ber2026andaftertheendof2030, respectively),ESA’snextgeneration X-ray observatory NewAthena is poised to transform X-ray astron- omy,andenablescientiststoexplore far fainter X-ray echoes in the out- skirtsofourgalaxy.  39 ﻛﺎﻧــﺖ ﻣﺠﺮﺗﻨــﺎ ﺗﻤﺘﻠــﻚ ذراﻋــ ﺣﻠـﺰوﻧﻴﺘ أم أرﺑﻌـ ﺔ أذرع ) وﻧﺤــﻦ ﻧﻌﺮف اﻵن أن اﻟﻌﺪد ﻫﻮ أرﺑﻌ (. ﺔ اﻵن وﺟ ـﺪت إﺣ ـﺪى ﻣﻬ ـﺎم وﻛﺎﻟــﺔ اﻟﻔﻀﺎء اﻷوروﺑﻴﺔ اﻷﺧـﺮى ﻃﺮﻳﻘـﺔ ﺟﺪﻳــﺪة ﻟﺮﺳــﻢ ﺧﺮﻳﻄــﺔ أﻃــﺮاف . ﻣﺠﺮﺗﻨﺎ ﻗﺎﻟﺖ ﺑﻴﺎﺗﺮﻳﺘﴚ ﻓﺎﻳـﺎ ﻣـﻦ ا ﻌﻬـﺪ اﻟـ ﻮﻃﻨﻲ اﻹﻳﻄـ ﺎﱄ ﻟﻠﻔﻴﺰﻳـﺎء اﻟﻔﻠﻜﻴﺔ اﻟﺘﻲ ﻗﺎدت ﻫﺬا اﻟﺒﺤﺚ ﺿﻤﻦ أﻃﺮ وﺣﺔ اﻟـﺪﻛﺘﻮراه اﻟﺨﺎﺻـﺔ ﺑﻬـﺎ : ﻋـﺎدة » ﻣـﺎ ﻧﺒﻨ ـﻲ ﻧﻤــﺎذج ﻟــﻸذرع اﻟﺨﺎرﺟﻴﺔ ﺠﺮة درب اﻟﺘﺒﺎﻧﺔ ﺑﺼﻮرة ﻏ ﻣﺒﺎﴍة اﻋﺘﻤﺎد ﻋﲆ اً ﻣﺎ ﻧﻌﺮﻓـﻪ ﻋﻦ ﻛﻴﻔﻴﺔ دوران ﻣﺠﺮﺗﻨﺎ ﻟﻜﻦ ﻫـﺬه اﻟﻄﺮﻳﻘﺔ ﺗﱰك ﻣﺠﺎﻻً ﻟﻠﺨﻄـﺄ وﺑـﺪﻻً ﻣﻦ ذﻟﻚ اﺗﺒﻌﻨﺎ ﻧﻬﺠـ ﺎً : اً ﺟﺪﻳـﺪ ﻓﻘـﺪ درﺳﻨﺎ آﺛﺎر ﺛﻼﺛﺔ اﻧﻔﺠـﺎرات ﻛﻮﻧﻴـﺔ وﻗﻌﺖ ﰲ ﻣﺠﺮات أﺑﻌﺪ ﺑﻜﺜ وأﻃﻠﻘﺖ ﻫﺬه اﻻﻧﻔﺠﺎرات أﺷﻌﺔ ﺳﻴﻨﻴﺔ ارﺗﺪت ﻋﱪ ﻋﺪة أذرع ﺧﺎرﺟﻴﺔ ﻟﺪرب اﻟﺘﺒﺎﻧﺔ وﻗﻤﻨـﺎ ﺑﻘﻴـﺎس ا ﺴــﺎﻓﺎت إﱃ ﻫـﺬه اﻷﺻﺪاء ﻣﺒﺎﴍة «. وﻗﺪ اﻧﺒﻌﺜﺖ اﻷﺷـﻌﺔ اﻟﺴـﻴﻨﻴﺔ ﻣـﻦ ﺛﻼﺛﺔ اﻧﻔﺠـﺎرات ﺷـﺪﻳﺪة اﻟﺴـﻄﻮع ﺗُﻌﺮف ﺑﺎﺳﻢ اﻧﻔﺠﺎر ات أﺷﻌﺔ ﻏﺎﻣـﺎ ﺛﻢ ارﺗﺪت اﻷﺷﻌﺔ اﻟﺴـﻴﻨﻴﺔ وﺗﺸـﺘﺖ ﺑﻔﻌﻞ ﺣﺒﻴﺒﺎت اﻟﻐﺒﺎر ا ﻮﺟﻮدة داﺧﻞ اﻷذرع اﻟﺤﻠﺰوﻧﻴﺔ ﺠﺮة درب اﻟﺘﺒﺎﻧﺔ ﻣﻜﻮِﻧﺔ ﺣﻠﻘﺎت ﺳﺎﻃﻌﺔ اﻟﺘﻘﻄﻬﺎ ﻛﻞ ﺎ ﻌ ﺣ ﺎ ﻛﻞ ﻣﻦ إﻛﺲ اﻟﺘ إم إم ﻧﻴﻮﺗﻦ - ا وﺗﺸﺎﻧﺪر وﻣـﻦ ﺧـﻼل دراﺳـﺔ ﻛﻴﻔﻴﺔ ﺗﻤﺪد ﻫﺬه اﻷ ﺻﺪاء اﻟﺤﻠﻘﻴﺔ ﺑﺒﻂء ﻣـﻊ ﻣﺮور اﻟﻮﻗﺖ ﺗﻤﻜﻨﺖ ﺑﻴﺎﺗﺮﻳﺘﴚ وزﻣﻼؤﻫﺎ ﻣﻦ ﺗﺤﺪﻳﺪ ا ﺴﺎﻓﺔ إﱃ ﺣﺒﻴﺒﺎت اﻟﻐﺒﺎر اﻟﺘﻲ ﺳﺒﺒﺖ اﻟﺘﺸﺘﺖ وﺑﻤﺎ أن ﻫﺬه اﻟﺤﺒﻴﺒﺎت ﺗﻘـﻊ داﺧـﻞ ﺳـﺤﺐ ﻣﻮﺟـﻮدة ﰲ أذرع ﻣﺠ ﺮﺗﻨـﺎ اﺳـﺘﻄﺎع اﻟﻔﺮﻳﻖ ﻗﻴﺎس ا ﺴﺎﻓﺎت إﱃ ﺗﻠﻚ اﻷذرع ﺑﺼﻮرة . ﻣﺒﺎﴍة وإﱃ ﺟﺎﻧﺐ ﺗﺄﻛﻴﺪ ا ﺴﺎﻓﺔ ا ﻌﺮوﻓـﺔ إﱃ ذراع ﺑﺮﺳﺎوس . وﺟﺪ اﻟﻌﻠﻤﺎء أن اﺛﻨ ﻣﻦ أذرع ﻣﺠﺮة درب اﻟﺘﺒﺎﻧﺔ وﻫﻤﺎ ذراع اﻟﻘـﻮس ﻗﻨﻄﻮرس اﻟﺨﺎرﺟﻲ واﻟﺬراع اﻟﺨﺎرﺟﻲ ﻳﻘﻌﺎن ﻋﲆ ﻣﺴﺎﻓﺔ أﺑﻌﺪ ﺑﻨﺴﺒﺔ ﺗﺼﻞ إﱃ 10 % ﻣﻤـﺎ ﻌﺘ ﻛﺎن ﻳ ﻘﺪ ﺳـﺎﺑﻘًﺎ . ورﻏـﻢ أن ﻣﻬﻤـﺔ ﻏﺎﻳـﺎ أﺣﺪﺛﺖ ﺛﻮرة ﰲ ﻓﻬﻤﻨﺎ ﺠﺮة درب اﻟﺘﺒﺎﻧﺔ، ﻓﺈن ﻗﻴﺎﺳﺎت ا ﺴﺎﻓﺎت اﻟﺘﻲ ﻳﻮﻓﺮﻫـﺎ اﻟﺘﻠﺴـﻜﻮب ﺣﺘﻰ اﻵن ﺗﻜﻮن أﻗﻞ دﻗـﺔ ﺑﺎﻟﻨﺴـﺒﺔ ﻟـﻸذرع ﺣﺘﻰ اﻵن ﺗﻜﻮن أﻗﻞ دﻗـﺔ ﺑﺎﻟﻨﺴـﺒﺔ ﻟـﻸذرع اﻟﺨﺎرﺟﻴﺔ . أﻣـﺎ اﺳـﺘﺨﺪام اﻷﺷـﻌﺔ اﻟﺴـﻴﻨﻴ ﺔ ﻟﻘﻴﺎس ا ﺴﺎﻓﺎت إﱃ ﺳﺤﺐ اﻟﻐﺒﺎر ﻛﻤﺎ ﻓﻌـﻞ ﻛﻞ ﻣﻦ إﻛﺲ إم إ -م ﻧﻴﻮﺗﻦ وﺗﺸـﺎﻧﺪرا ﰲ ﻫـﺬه اﻟﺪراﺳﺔ ﻓﻴﻮﻓﺮ دﻗﺔ ﻋﺎﻟﻴﺔ ﺣﺘﻰ ﻋﻨﺪ ا ﺴﺎﻓﺎت اﻟﺒﻌﻴﺪة ﻣﻤﺎ أﺗﺎح ﻟﻔﺮﻳﻖ اﻟﺒﺤﺚ إﻋـﺎدة رﺳـﻢ ﺧﺮﻳﻄﺔ ا ﻨﺎﻃﻖ اﻟﺨﺎرﺟﻴﺔ ﻟﻠﻤﺠﺮة . ﻗﺎل إرﻳﻚ ﻛﻮﻟﻜﺮز ﻋﺎﻟﻢ ﻣﴩوع إﻛـﺲ إم إم - ﻧﻴﻮﺗﻦ ﰲ وﻛﺎﻟﺔ اﻟﻔﻀﺎء اﻷ »: وروﺑﻴﺔ ﻳﻤﺜﻞ ﻫﺬا اﻻﻛﺘﺸﺎف ﻣﺜﺎﻻً ﺎً راﺋﻌ ﻋﲆ أن ا ﻬـﺎم اﻷﻗـﺪم اﻟﺘﺎﺑﻌﺔ ﻟﻮﻛﺎﻟﺔ اﻟﻔﻀﺎء اﻷوروﺑﻴﺔ، ﻣﺜﻞ إﻛـﺲ إم إم - ﻧﻴﻮﺗﻦ اﻟﺬي أُﻃﻠﻖ ﻋـﺎم 1999 ﻻ ﺗـﺰال ﺗﺆدي دور اً ﺑﺎﻟﻎ اﻷﻫﻤﻴﺔ ﰲ اﺳﺘﻜﺸﺎف اﻟﻜﻮن . واﻵن، وﰲ ﻋﻘﺪه اﻟﺜﺎﻟﺚ ﻣـ ﻦ اﻟﻌﻤـﻞ ﻳﻮاﺻـﻞ إﻛﺲ إم إم - ﻧﻴﻮﺗﻦ ﺗﻘﺪﻳﻢ ﺗﺪﻓﻖ ﻣﺴـﺘﻤ ﺮ ﻣـﻦ اﻻﻛﺘﺸﺎﻓﺎت اﻟﻌﻠﻤﻴﺔ اﻟﺮاﺋـﺪة ﺑـﺪء اً ﻣـﻦ أ ـﻊ اﻧﻔﺠـﺎر ﻷﺷـﻌﺔ ﻏﺎﻣـﺎ ﺟـﺮى رﺻـﺪه ﻋـﲆ اﻧﻔﺠﺎر ﻷﺷﻌﺔ ﻏﺎﻣﺎ ﺟﺮى رﺻﺪه ﻋﲆ اﻹﻃﻼق ﺑﺎﻟ اً ﻣﺮور ﻨﺠﻮم اﻟﺘﻲ ﺗﻤﺰﻗﻬﺎ اﻟﺜﻘﻮب اﻟﺴﻮداء وﺻﻮﻻً إﱃ ﻟﻘﻄ ﺎت ﺑﺎﻷﺷﻌﺔ اﻟﺴﻴﻨﻴﺔ ﻟﻜﻮﻛـﺐ ا ﺮﻳﺦ وﻳﺼﺒﺢ اﻷﻣﺮ أﻛﺜﺮ أﻫﻤﻴﺔ ﻋﻨﺪﻣﺎ ﺗﻌﻤﻞ ا ﻬﺎم ﻣﻌ ﺎً ﻛﻤﺎ ﺣـﺪث ﻫﻨـ ﺎ إذ ﻳﻤﻜﻨﻬـﺎ ﻣﻌًـﺎ اﻟﻜﺸﻒ ﻋﻦ ﻛﻢ ﻫﺎﺋﻞ ﻣـ ﻦ ا ﻌﻠﻮﻣـﺎت ﺣـﻮل اﻟﺴﻤﺎء ﻣﻦ ﺣﻮﻟﻨـﺎ « . ﻓـﺈﱃ ﺟﺎﻧـﺐ اﻟﺒﻴﺎﻧـﺎت اﻷﻛﺜــﺮ ﺗﻔﺼــﻴﻼً اﻟﺘــﻲ ﺳﺘﺼــﺪر ﺿــﻤﻦ اﻹﺻﺪارﻳﻦ اﻟﺮاﺑﻊ واﻟﺨﺎﻣﺲ ﻣﻦ ﺑﻴﺎﻧﺎت ﻏﺎﻳـﺎ ) ا ﻘﺮر ﻧـ ـ ﴩﻫﻤﺎ ﰲ دﻳﺴـﻤﱪ 2026 وﺑﻌـﺪ ﻧﻬﺎﻳﺔ ﻋﺎم 2030 ﻋﲆ اﻟﺘﻮاﱄ ( ﻳﺴﺘﻌﺪ ﻣ ﺮﺻـﺪ اﻷﺷﻌﺔ اﻟﺴﻴﻨﻴﺔ ﻣﻦ اﻟﺠﻴﻞ اﻟﺘﺎﱄ اﻟﺘﺎﺑﻊ ﻟﻮﻛﺎﻟﺔ اﻟﻔﻀﺎء اﻷوروﺑﻴﺔ " ﻧﻴﻮأﺛﻴﻨـﺎ " ﻹﺣـﺪاث ﻧﻘﻠـﺔ ﻧﻮﻋﻴﺔ ﰲ ﻋﻠﻢ ﻓﻠﻚ اﻷﺷﻌﺔ اﻟﺴـﻴﻨﻴﺔ وﺗﻤﻜـ اﻟﻌﻠﻤﺎء ﻣﻦ دراﺳﺔ أﺻﺪاء أﺷﻌﺔ ﺳﻴﻨﻴﺔ أﻛﺜـﺮ ﺧﻔﻮﺗًﺎ ﰲ أﻃﺮاف ﻣﺠﺮة درب اﻟﺘﺒﺎﻧﺔ . - ﺳﺒﺘﻤﺒﺮ ﺃﻛﺘﻮﺑﺮ 2 0 2 6 ﺗﻌﺮض ﻫﺬﻩ اﻟﺮﺳﻮﻣﺎت اﻟﺘﺨ ﻠ ﺔ ﻨ ﺔ ﻣﺠﺮﻨﺎ در اﻟﺘ ﺎﻧﺔ اﺳﺘﻨﺎداً ـﺎ اﻟﺘـﺎﺑﻊ ﻟﻮ ﺎﻟـﺔ اﻟﻔﻀـﺎء إﻟـﻰﺑ ﺎﻧـﺎت ﻣـﻦ ﻣﺮﺻـﺪ ﻏﺎ ــﺔ اﻷوروﺑ ــﻒﻋـــﺪل اﻟﻌﻠﻤــﺎء ﻣﻮﻗـــﻊ أذرﻋﻬــﺎ اﻟـــ ﻛ وﺗﺒـــ ـ ﺨﺎرﺟ ﺔ ﻔﻀــﻞ رﺻـــﺪ ﻣﺮﺻــﺪ إﻛـــﺲ إم إم ﻧﻴــﻮﺗﻦ اﻟﺘـــﺎﺑﻊ ﻟﻮ ﺎﻟـــﺔ ـــﺔ وﻣﺮﺻـــﺪ ﺗﺸـــﺎﻧﺪرا اﻟﺘـــﺎﺑﻊ ﻟﻮ ﺎﻟـــﺔ ﻧﺎﺳـــﺎ اﻟﻔﻀـــﺎء اﻷوروﺑ . ـــﺔ رﺻـــﺪ ﻣﺮﺻـــﺪا اﻷﺷـــﻌﺔ اﻟﺴـــ ﻨ ﺔ آﺛـــﺎرﺛﻼﺛـــﺔ اﻧﻔﺠـــﺎرات ﻮﻧ ﺳﺎﻃﻌﺔ ﺗ دد أﺻﺪاؤﻫﺎ ﻋ اﻷذرع اﻟ ـ ﺤﻠﺰوﻧ ﺔ اﻟ ـ ﺨﺎرﺟ ﺔ ﻟﻤﺠﺮﻨﺎ وﻣﻦﺧﻼل ﻗ ﺎس اﻟﻤﺴﺎﻓﺔ إﻟﻰﻫﺬﻩ اﻷﺻـﺪاء وﺟـﺪ أن اﻷذرع اﻟ ﻓﺮﻖ ﺑﺤ ـ ﺨﺎرﺟ ﺔ أ ﻌﺪ ﻨﺴ ﺔ ﺗﺼﻞ إﻟﻰ 10 % ﻣﻤﺎ ﻛﻨﺎ ﻧﻌﺘﻘﺪ . [ESA/Gaia/ DPAC, Stefan Payne-Wardenaar, ESA/XMM-Newton and NASA/Chandra]