Free Astronomy Magazine July-August 2022 ARABIC VERSION

Stellar-mass black holes are usually found with companion stars, making this one unusual. The newly detected wandering black hole lies about 5,000 light- years away, in the Carina-Sagittarius spiral arm of our galaxy. However, its discovery allows astronomers to es- timate that the nearest isolated stel- lar-mass black hole to Earth might be as close as 80 light-years away. The nearest star to our solar system, Proxima Centauri, is a little over 4 light-years away. Black holes roaming our galaxy are born from rare, monstrous stars (less than one-thousandth of the galaxy’s stellar population) that are at least 20 times more massive than our Sun. These stars explode as supernovae, and the remnant core is crushed by gravity into a black hole. Because the self-detonation is not perfectly symmetrical, the black hole may get a kick, and go careening through our galaxy like a blasted cannonball. Telescopes can’t photograph a way- ward black hole because it doesn’t emit any light. However, a black hole warps space, which then de- flects and amplifies starlight from anything that momentarily lines up exactly behind it. Ground-based telescopes, which monitor the brightness of millions of stars in the rich star fields toward the central bulge of our Milky Way, look for a tell-tale sudden brighten- ing of one of them when a massive object passes between us and the star. Then Hubble follows up on the most interesting such events. Two teams used Hubble data in their . The warping of space due to the gravity of a foreground object pass- ing in front of a star located far be- hind it will momentarily bend and amplify the light of the background star as it passes in front of it. As- tronomers use the phenomenon, called gravitational microlensing, to study stars and exoplanets in the ap- proximately 30,000 events seen so far inside our galaxy. The signature of a foreground black hole stands out as unique among other microlensing events. The very intense gravity of the black hole will stretch out the duration of the lens- ing event for over 200 days. Also, if the intervening object was instead a foreground star, it would cause a transient color change in the ﻋﺎدة ﻣﺎ ﺗﻮﺟـﺪ اﻟﺜﻘـﻮب اﻟﺴـﻮداء ذات اﻟﻜﺘـﻞ اﻟﻨﺠﻤﻴﺔ ﻣﻊ اﻟﻨﺠﻮم اﳌﺼﺎﺣﺒﺔ ، ﳑﺎ ﻳﺠﻌﻞ ﻫﺬا واﺣـــﺪًا ﻏـــﲑ ﻋـــﺎدي . ﻳﻮﺟـــﺪ اﻟﺜﻘـــﺐ اﻷﺳـــﻮد اﳌﺘﺠﻮل اﳌﻜﺘﺸﻒ ﺣﺪﻳﺜًﺎ ﻋﲆ ﻣﺴـﺎﻓﺔ ﺣـﻮاﱄ ٥٠٠٠ ﺳــﻨﺔ ﺿـﻮﺋﻴﺔ اﻟـﺬراع اﳊﻠﺰوﻧﻴـﺔ راﻣـﻲ اﻟﻘــــﻮس ﻟ ﻔــــﻲ ﳎ ، ﺮﺗﻨــــﺎ وﻣــــﻊ ذﻟــــﻚ ، ﻓــــﺈن اﻛﺘﺸــﺎﻓﻪ ﻳﺴـﻤﺢ ﻟﻌﻠﻤــﺎء اﻟﻔﻠـﻚ ﺑﺘﻘــﺪﻳﺮ أن أﻗﺮب ﺛﻘﺐ أﺳﻮد ذو ﻛﺘﻠﺔ ﻧﺠﻤﻴﺔ ﻣﻨﻔـﺮد ﻋـﻦ اﻷرض ﻗـﺪ ﻳﻜـﻮن ﻋــﲆ ﺑﻌــﺪ ٨٠ ﺳـﻨﺔ ﺿـﻮﺋﻴﺔ أﻗﺮب ﻧﺠـﻢ إﱃ ﻧﻈﺎﻣﻨـﺎ اﻟﺸﻤﴘـ ﺑﺮوﻛﺴـﻴﻤﺎ ﻗﻨﻄﻮروس ﻳﺒﻌﺪ ﻣﺎ ﻳﺰﻳﺪ ﻗﻠﻴﻼً ﻋﻦ ٤ ﻨﻮات ﺳ . ﺿﻮﺋﻴﺔ ﺗﻮﻟﺪ اﻟﺜﻘـﻮب اﻟﺴـﻮداء اﻟـﱵ ﺗﺘﺠـﻮل ﳎﺮﺗﻨﺎ ﻣﻦ ﻧﺠـﻮم ﻧـﺎدرة وﺣﺸـﻴﺔ ) أﻗـﻞ ﻣـﻦ واﺣـﺪ اﻷﻟـﻒ ﻣـﻦ ﻋــﺪد اﻟﻨﺠـﻮم اﳌﺠـﺮة ( واﻟﱵ ﺗﺰﻳﺪ ﻛﺘﻠﺘﻬﺎ ﻋﻦ ﺷﻤﺴﻨﺎ ﺑﻌﴩﻳﻦ ﻣـﺮة ﻋـﲆ اﻷﻗـﻞ ﺗﻨﻔﺠـﺮ ﻫـﺬه اﻟﻨﺠـﻮم ﻋـﲆ ﺷـﻜﻞ ﻣﺴــــﺘﻌﺮات ﻋﻈﻤــــﻰ وﻳــــﺘﻢ ﺳــــﺤﻖ اﻟﻨــــﻮاة اﳌﺘﺒﻘ ﻴــﺔ ﺑﻮاﺳــﻄﺔ اﳉﺎذﺑﻴــﺔ ﺛﻘــﺐ أﺳــ ﻮد ــــ ــــ ﻧﻈﺮًا ﻷن اﻟﺘﻔﺠﲑ اﻟـﺬاﰐ ﻟـﻴﺲ ﻣﺘﻤـﺎﺛﻼً ﲤﺎﻣًـﺎ ﻓﻘـــﺪ ﻳﺤﺼـــﻞ اﻟﺜﻘـــﺐ اﻷﺳـــﻮد ﻋـــﲆ دﻓﻌـــﺔ وﻳﺘﺤـــﺮك ﻋـــﱪ ﳎﺮﺗﻨـــﺎ ﻣﺜـــﻞ ﻗﺬﻳﻔـــﺔ ﻣـــﺪﻓﻊ ، ﻣﺘﻔﺠﺮة ﻻ ﺗﺴﺘﻄﻴﻊ اﻟﺘﻠﺴﻜﻮﺑﺎت ﺗﺼﻮﻳﺮ اﻟ ﺜﻘـﺐ اﻷﺳـﻮد ﻳ ﻷﻧـﻪ ﻻ ﺼـﺪر أي ﺿـﻮء وﻣـﻊ ذﻟــﻚ ، ﻓــﺈن اﻟﺜﻘــﺐ اﻷﺳــﻮد ﻳﺸــﻮه اﻟﻔﻀــﺎء واﻟـﺬي ﺑـﺪوره ﻳ ﺤـﺮف وﻳﻀـﺨﻢ ﺿـﻮء اﻟﻨﺠـﻮم ﻋﻨــــﺪﻣﺎ ﺗﺼــــﻄﻒ ﺑﺸــــﻜﻞ ﻣﺆﻗــــﺖ ﺧﻠﻔــــﻪ ﺑﺎﻟﻀـﺒﻂ . اﻟﺘﻠﺴـﻜﻮﺑﺎت اﻷرﺿـﻴﺔ اﻟـﱵ ﺗﺮاﻗـﺐ ﺳــﻄﻮع ﻣﻼﻳــﲔ اﻟﻨﺠــﻮم ﺣﻘــﻮل اﻟﻨﺠــﻮم اﻟﻐﻨﻴﺔ ﺑﺎﺗﺠﺎه اﻻﻧﺘﻔـ ﺎخ اﳌﺮﻛـﺰي ﳌﺠﺮﺗﻨـﺎ درب اﻟﺘﺒﺎﻧــﺔ ﺗﺒﺤـﺚ ﻋــﻦ ﺳـﻄﻮع ﻣﻔــﺎ ﻷﺣــﺪﻫﺎ وذﻟــﻚ ﻋﻨــﺪ ﻣﺎ ﳝــﺮ ﺟﺴــﻢ ﺿــﺨﻢ ﺑﻴ ﻨــﺎ وﺑــﲔ اﻟﻨﺠﻢ ﰒ ﻳﺘﺎﺑﻊ ﺗﻠﺴﻜﻮب ﺗﻠﻚ ﻫﺎﺑﻞ اﻷﺣـ ﺪاث ﺑﺸـﻜﻞ داﰂ وﻳﺠﻤــﻊ ﺑﻴﺎﻧﺎﺗﻬـﺎ ﺑﺸـﻜﻞ أﻓﻀـﻞ ﻟﻘـــﺪ اﺳـــﺘﺨﺪم ﻓﺮﻳﻘـــﺎن ﺑﻴﺎﻧـــﺎت ﺗﻠﺴـــﻜﻮب ﻫﺎﺑـــﻞ ﺗﺤﻘﻴﻘﺎﺗﻬﻤـــﺎ - أﺣـــﺪﻫﻤﺎ ﺑﻘﻴـــﺎدة ﻛﺎﻳﻼش ﺳﺎﻫﻮ ﻣﻦ ﻣﻌﻬـﺪ ﻋﻠـﻮم اﻟﺘﻠﺴـﻜﻮب ـــ ــــــــــ اﻟﻔﻀــــﺎﰄ ﺑــــﺎﻟﺘﻴﻤﻮر ﺑﻮﻻﻳــــﺔ ﻣﺎرﻳﻼﻧــــﺪ واﻵﺧـــﺮ ﺑﻮاﺳـــﻄﺔ ﻛﻴﴘـــ ﻻم ﻣـــﻦ ﺟﺎﻣﻌـــﺔ ﻛﺎﻟﻴﻔﻮرﻧﻴــﺎ ، ﺑــﲑﻛﲇ ، وﻟﻜــﻦ ﺗﺨﺘﻠــ ﻒ ﻧﺘــﺎﺋﺞ اﻟﻔـــﺮﻳﻘﲔ ﻗﻠـــﻴﻼً ﻟﻜـــﻦ ﻛﻼﻫﻤـــﺎ ﻳﺸـــﲑ إﱃ وﺟﻮد ﺟﺴﻢ . ﻛﺜﻴﻒ إن اﻟﺘﻮاء اﻟﻔﻀﺎء ﺑﺴ ﺐ ﺟﺎذﺑﻴـﺔ ﺟﺴـﻢ ﳝــﺮ أﻣـﺎم ﻧﺠـﻢ ﻣﻮﺟـﻮد ﺑﻌﻴــﺪًا ﺧﻠﻔـﻪ ﺳــﻮف ﻳﻨﺤـﲏ ﻣﺆﻗﺘًــﺎ وﻳﻀـﺨﻢ ﺿــﻮء ذﻟــﻚ اﻟــ ﻨﺠﻢ أﺛﻨــﺎء ﻣــﺮوره أﻣﺎﻣــﻪ . ﻳﺴــﺘﺨﺪم اﻟﻔﻠﻜﻴـﻮن ﻫـﺬه اﻟﻈـﺎﻫﺮة اﳌﺴـﻤﺎة اﻟﻌﺪﺳـﺔ اﻟﺪﻗﻴﻘﺔ ﻟﻠﺠﺎذﺑﻴﺔ ﻟﺪراﺳﺔ اﻟﻨﺠﻮم و اﻟﻜﻮاﻛﺐ اﳋﺎرﺟﻴﺔ ﻣﺎ ﻳﻘﺮب ﻣﻦ ٣٠٠٠٠ ﺣـﺪث ﺷـﻮﻫﺪ ﺣـﱴ اﻵن داﺧـﻞ ﳎﺮﺗﻨـﺎ تﺑـﺮز . ﺑﺼـﻤﺔ اﻟﺜﻘـﺐ اﻷﺳـﻮد اﳌﻘﺪﻣـﺔ ﻋـﲆ أﻧـﻪ ﻓﺮﻳـﺪ ﻣـﻦ ﻧﻮﻋـﻪ ﺑـــﲔ أﺣــــﺪاث اﻟﻌﺪﺳـــﺔ اﻟﺪﻗﻴﻘــــﺔ اﻷﺧــــﺮى . ﺳـﺘﻌﻤﻞ اﳉﺎذﺑﻴـﺔ اﻟﺸـﺪﻳﺪة ﻟﻠﺜﻘـﺐ اﻷﺳـﻮد ﻋﲆ إﻃﺎﻟﺔ ﻣﺪة ﺣﺪث اﻟﻌﺪﺳـﺔ ﻷﻛـﱶ ﻣـﻦ ٢٠٠ . ﻳـﻮم أﻳﻀًــﺎ ، إذا ﻛــﺎن اﳉﺴــ ﻢ اﳌﺘــﺪاﺧﻞ ﺑــﺪﻻً ﻣــﻦ ذﻟــﻚ ﻧﺠﻤًــﺎ أﻣﺎﻣﻴًــﺎ ﻓﺴــﻴﺆدي ذﻟــﻚ إﱃ ﺗﻐﻴــﲑ ﻋــﺎﺑﺮ ﻟﻠــﻮن ﺿــﻮء اﻟﻨﺠــﻮم ﻛﻤــﺎ ﰎ ﻗﻴﺎﺳــﻪ ﻷن اﻟﻀــﻮء ﻣــﻦ اﻟﻨﺠــﻮم اﻷﻣﺎﻣﻴـــﺔ و اﳋﻠﻔﻴﺔ ﺳـﻮف ﳝﱱﺟـﺎن ﻣﻌًـﺎ ﻣﺆﻗﺘًـﺎ ، ﻟﻜـﻦ ﱂ ﻳﻼﺣــــﻆ ﺣــــﺪوث أي ﺗﻐــــﲑ ات اﻟﻠــــﻮن ﻣﻨﻄﻘﺔ ﺣﺪث اﻟﺜﻘﺐ اﻷﺳﻮد . رﺳــــﻢﻓــــ ﻟ ﺜﻘــــﺐ أﺳــــﻮد ﻨﺠــــﺮفﻋــــ ﻣﺠﺮ ﻨـــــﺎ در اﻟﺘ ﺎﻧـــــــــﺔ . ـــــــــﺎ اﻟﺜﻘـــــــــﺐ اﻷﺳـــــــــﻮدﻫـــــــــﻮ اﻟ ﻘﺎ اﻟﻤﺤﻄﻤــــــﺔ ﻟـــــــﻨ ﻢﻫﺎﺋـــــــﻞ اﻧﻔﺠــــــﺮﻋﻠـــــــﻰﺷـــــــ ﻞ ﻣﺴــﺘﻌﺮأﻋﻈـﻢ . ــﺔ ﺗﺴـﺎويﻋــﺪة اﻟﻨـﻮاة اﻟ ﺎﻗ أﺿﻌﺎفﻛﺘﻠـﺔﺷﻤﺴـﻨﺎ . ﻳﺤـ ﺲاﻟﺜﻘـﺐ اﻷﺳـﻮد اﻟﻀﻮء ﺴ ﺐﻣﺠﺎلﺟﺎذﺑ ﺘﮫ اﻟﺸـﺪ ﺪة . ﺸـﻮﻩ ــــــﮫ ، ﻣﻤــــــﺎ اﻟﺜﻘــــــﺐ اﻷﺳــــــﻮد اﻟﻔﻀــــــﺎء اﻟﻤﺤــــــ ﻂ إﻟــــﻰﺗﺸــــﻮﻩ ﺻــــﻮر ﻳــــﺆد اﻟ ﻨﺠــــﻮم اﻟﻤﺼــــﻄﻔﺔ ﺧﻠﻔــــــ ًــــــﺎ ﮫ ﻣ ﺎﺷــــــﺮة ﺗﻘﺮ . ﻘــــــﺪم ﺗــــــﺄﺛ ﻋﺪﺳــــــﺔ ــــــ ا ﺎذﺑ ﺔ ــــــﺪ ﻋــــــﻦ وﺟــــــﻮد ﺛﻘـــــــﻮب اﻟــــــﺪﻟﻴﻞ اﻟﻮﺣ ﺳــﻮ ــﺪة ﺗ داء وﺣ ﺘ ﺠـــﻮل ﻓــﻲﻣﺠﺮ ﻨـــﺎ ﻗـــﺪ واﻟــ ــــﻮن ﻋـــــﺪد ﻳ ﻫــــﺎ ١٠٠ . ﻣﻠﻴـــــﻮن ﺴــــﻌﻰﺗﻠﺴـــــ ﻮب ﻫﺎﺑــــــﻞ اﻟ ﻔﻀــــــﺎﺋﻲ ا ﻟﺒﺤــــــﺚﻋـــــﻦﻫــــــﺬﻩ اﻟﺜﻘــــــﻮب اﻟﺴــــﻮداء ﻣــــﻦﺧــــﻼل اﻟﺒﺤــــﺚﻋـــﻦ ﺗﺸــــﻮ ﮫ ﻓــــﻲ ﺿﻮء اﻟﻨﺠـﻮم ﻋﻨـﺪﻣﺎ ﺗﻨﺠـﺮف اﻟﺜﻘـﻮب اﻟﺴـﻮداء أﻣﺎﻣ .ﻬﺎ [ESA/Hubble, Digitized Sky Survey, Nick Risinger (skysurvey.org ), N. Bartmann] ﻳﻮﻟﻴﻮ – أﻏﺴﻄﺲ 2022 ٢٧