Free Astronomy Magazine September-October 2022 ARABIC VERSION

spread out and diffuse, especially in the outer regions of galaxies, where the gas and dust become sparse and thus fainter. For some nearby galax- ies, that meant Herschel missed up to 30% of all the light given off by dust. With such a significant gap, as- tronomers struggled to use the Her- schel data to understand how dust and gas behaved in these environ- ments. To fill out the Herschel dust maps, the new images combine data from three other missions: ESA’s re- tired Planck observatory, along with two retired NASA missions, the In- frared Astronomical Satellite (IRAS) and Cosmic Background Explorer (COBE). The images show the An- dromeda galaxy, also known as M31; the Triangulum galaxy, or M33; and the Large and Small Magellanic Clouds – dwarf galaxies orbiting the Milky Way that do not have the spi- ral structure of the Andromeda and ﻣﺠﻠﺔ Astronomy ﺎﻟﻌﺮ ﺔ ٤٨ اﻷﻛﺜﺮ ﺧ ا ﺗﺘﻤﺪد ﺎﺻﺔ ﰲ ا ﻨـﺎﻃﻖ اﻟﺨﺎرﺟﻴـﺔ ﻟﻠﻤﺠﺮات ﺣﻴﺚ ﻳﺼﺒﺢ اﻟﻐﺎز واﻟﻐﺒﺎر ﻣﺘﻨـﺎﺛﺮًا وﺑﺎﻟﺘـﺎﱄ ﻳﺼـﺒﺢ ﺧﺎﻓﺘًـﺎ . ﺑﺎﻟﻨﺴـﺒﺔ ﻟـﺒﻌﺾ ا ﺠﺮات اﻟﻘﺮﻳﺒﺔ ، ﻛﺎن ﻫﺬا ﻳﻌﻨﻲ أن ﻣﺮﺻـﺪ ﻫ ﺷﻞ ﻓﻘﺪ ﻣﺎ ﻳﺼـﻞ إﱃ ٣٠ ٪ ﻣـﻦ اﻟﻀـﻮء ا ﻨﺒﻌﺚ ﻣﻦ اﻟﻐﺒﺎر . ﻣﻊ ﻫﺬه ا ﻟﻔﺠﻮة اﻟﻜﺒـ ة ﻛﺎﻓﺢ ﻋﻠﻤﺎء اﻟﻔﻠﻚ ﻻﺳﺘﺨﺪام ﺑﻴﺎﻧﺎت ﻣﺮﺻـﺪ ﻫ ﺷﻞ ﻟﻔﻬﻢ ﻛﻴﻔﻴﺔ ﺳﻠﻮك اﻟﻐﺒﺎر واﻟﻐـﺎز ﰲ ﻫﺬه اﻟﺒﻴﺌـﺎت . ـﻞء ﺧـﺮاﺋﻂ ﻏﺒـﺎر ﻣﺮﺻـﺪ ﻫ ﺷﻞ ، ﺗﺠﻤﻊ اﻟﺼﻮر اﻟﺠﺪﻳﺪة ﺑﻴﺎﻧﺎت ﻣـﻦ ﺛﻼث ﺑﻌﺜﺎت أﺧـﺮى : ﻣﺮﺻـﺪ ﺑﻼﻧـﻚ اﻟﺘـﺎﺑﻊ ﻟﻮﻛﺎﻟﺔ اﻟﻔﻀﺎء اﻷوروﺑﻴـﺔ ، ﺟﻨﺒًـﺎ إﱃ ﺟﻨـﺐ ـــــــــ ﻣﻊ ﺑ ﻌﺜﺘﺎن ﻣﺘﻘﺎﻋﺪﺗﺎن ﻣـﻦ ﺑﻌﺜـﺎت وﻛﺎﻟـﺔ ﻧﺎﺳـﺎ، اﻟﻘﻤـﺮ اﻟﺼـﻨﺎﻋﻲ ﺑﺎﻷﺷــﻌﺔ ﺗﺤـﺖ اﻟﺤﻤــﺮاء ) IRAS ( إﺿــﺎﻓﺔ إﱃ ﻣﺴﺘﻜﺸــﻒ اﻟﺨﻠﻔﻴ ـﺔ اﻟﻜﻮﻧﻴــﺔ ) COBE ( . ﺣﻴ ـﺚ ﺗُﻈﻬــﺮ اﻟﺼﻮر ﻣﺠﺮة أﻧﺪروﻣﻴـﺪا ، ا ﻌﺮوﻓـﺔ أﻳﻀًـﺎ ــــ ﺑﺎﺳ ـﻢ ﻣﻴﺴــﻴﻴﻪ ٣١، وﻣﺠــﺮة ا ﺜﻠ ـﺚ ، أو ﻣﻴﺴــﻴﻴﻪ ٣٣ ؛ وﻏﻴــﻮم ﻣــﺎﺟﻼن اﻟﻜــﱪى واﻟﺼﻐﺮى ا ﺠ - ﺮات اﻟﻘﺰﻣﺔ اﻟﺘﻲ ﺗﺪور ﺣﻮل ﻣﺠﺮة درب اﻟﺘﺒﺎﻧـﺔ اﻟﺘـﻲ ﻻ ﺗﺤﺘـﻮي ﻋـﲆ اﻟﺒﻨﻴﺔ اﻟﺤﻠﺰوﻧﻴﺔ ﻷﻧﺪروﻣﻴﺪا و ﻣﺠﺮة ا ﺜﻠـﺚ ـ ﺳﺒﺘﻤ أﻛﺘﻮﺑﺮ 2022 ﺳﺤﺎ ﺔ ﻣﺎﺟﻼن اﻟﺼﻐﺮى ﺗﺎ ﻌﺔ ﻟﻤﺠﺮة در اﻟﺘ ﺎﻧﺔ ، ﻳﺤﺘﻮيﻋﻠﻰﺣﻮاﻟﻲ ٣ ﻣﻠ ﺎرات ﻧ ﻢ . ﺗُﻈﻬﺮﻫﺬﻩ اﻟﺼﻮرة ﺎﻷﺷــــﻌﺔ ﺗﺤــــﺖ اﻟــــ ـ ــــﺎرد ــــﺎراﻟ ــــﺪة واﻟﺮادﻳــــﻮ اﻟﻐ ﻤﺮاء اﻟ ﻌ ) اﻷﺧﻀــــﺮ ( واﻟــــﺪاﻓﺊ اﻷزرق ) ( ﺎﻹﺿــــﺎﻓﺔ إﻟــــﻰﻏــــﺎز ــﺪروﺟ اﻟﻬ ) اﻷ ﻤــﺮ .( ـﻮن اﻟﺼــﻮر ﺗﺘ ــﺔ ة ﻣــﻦ ﺑ ﺎﻧــﺎت ﻣــﻦ ﻌﺜــﺔ ﻫ ﺷــﻞ اﻟﺘﺎ ﻌــﺔ ﻟﻮ ﺎﻟــﺔ اﻟﻔﻀــﺎء اﻷوروﺑ ﻣــﻊ ﻣـــﻦ ﻣﺘﻘﺎﻋـــﺪﺗ ـــﺔ وﻣﻬﻤﺘـــ اﺳــﺘ ﻤﺎﻟﻬﺎ ﺑﺒ ﺎﻧـــﺎت ﻣـــﻦ ﻣﺮﺻـــﺪ ﻼﻧــﻚ اﻟﻤﺘﻘﺎﻋـــﺪ اﻟﺘـــﺎﺑﻊ ﻟﻮ ﺎﻟـــﺔ اﻟﻔﻀــﺎء اﻷوروﺑ ﻌﺜــــﺎت ﻧﺎﺳــــﺎ : اﻟﻤﺴــــﺢ ﺎﻷﺷــــﻌﺔ ﺗﺤــــﺖ اﻟــــ ـ ــــﺔ ، ﺎﻹﺿــــﺎﻓﺔ إﻟــــﻰ ــــﺔ اﻟ ﻮﻧ ﻤﺮاء وﻣﺴﺘﻜﺸــــﻒ ا ﻠﻔ اﻟﺘﻠﺴــــ ﻮ ﺎت اﻟﺮادﻳﻮ ﺔ ﺎر و ﻛﺲ ﻣ ﻤﻮﻋﺔ ﺗﻠﺴ ﻮ ﺎت أﺳ اﻟ ﺎ اﻟﻤﺪﻣﺠﺔ واﻟﺘﻠﺴ ﻮب اﻟﺮادﻳﻮي NANTEN . [ESA, NASA, NASA-JPL, Caltech, Christopher Clark (STScI), S. Stanimirovic (UW-Madison), N. Mizuno (Nagoya University)]