Free Astronomy Magazine July-August 2025 ARABIC VERSION

A The surprising origins of asteroid 2024 YR 4 byKeckObservatory stronomersusingW.M.Keck Observatory on Maunakea, Hawai ‘ iIslandhavedeter- minedthephysicalpropertiesand potential origin of 2024 YR 4 , the Earth-crossingasteroidfirstdiscov- eredbyscientistsinDecember2024. ThestudyrevealsYR 4 isasolid,stony type that likely originated from an asteroid family in the central Main BeltbetweenMarsandJupiter,are- gion not previously known to pro- duce Earth-crossing asteroids. “YR 4 spins once every 20 minutes, rotatesinaretrogradedirection,has a flattened, irregular shape, and is thedensityofsolidrock,” saidBryce Bolin, research scientist with Eureka Scientific and lead author of the study. “The shape of the asteroid provides us with clues as to how it formed, and what its structural in- tegrity is. Knowing these properties is crucial for determining how much effortorwhatkindoftechnique needstobeusedtodeflecttheas- teroid if it is deemed a threat.” Despitebeingascenariowidelypon- deredbyastronomersandHolly- wood writers for decades, further observationshavesincedetermined YR 4 willnotimpacttheEarthin2032 asoriginallypredicted.However, there is a ~2% chance it could hit the Moon instead. “Atabout50-60metersindiameter (similar to the width of a football field),it’soneofthelargestobjects inrecenthistorythatcouldhitthe Moon,” added Bolin. “If it does, it wouldgivescientistsararechance tostudyhowthesizeofanasteroid relatestothesizeofthecrateritcre- ates—something we haven’t been able to measure directly before.” Asteroidsthatare100metersor larger are often what astronomers call“rubblepiles,”madeupoffrag- mentsfromalargerparentasteroid thatbrokeapartinacollision.The ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ 26 اﻷﺻﻮل اﻟﻤﻔﺎﺟﺌﺔ ﻟﻠ ﻮ ﻜﺐ YR4 2024 : ﻘﻠﻢ ﻣﺮﺻﺪ د ﻠﻴﻮ ) ﻛ ﻚ. إم. ﻣﺮﺻﺪ ﻛ ﻚ ( ﺣـﺪد ﻋﻠﻤﺎء ﻓﻠﻚ ﻳﺴﺘﺨﺪﻣﻮن ﻣ ﺮﺻـﺪ دﺑﻠﻴـﻮ . إم. ﻛﻴ ـﻚ ﰲ ﻣﻮﻧ ـﺎ ﻛﻴ ـﺎ ﰲ ﺟﺰﻳ ـﺮة ﻫ ـﺎواي اﻟﺨﺼـﺎﺋﺺ اﻟﻔﻴﺰﻳﺎﺋﻴ ـﺔ واﻷﺻـﻞ ا ﺤﺘﻤ ـﻞ ﻟﻠﻜﻮﻳﻜــﺐ 2024 YR4 اﻟﻜﻮﻳﻜــﺐ اﻟﻌــﺎﺑﺮ ﻟﻸرض اﻟﺬي اﻛﺘﺸـﻔﻪ اﻟﻌﻠﻤـﺎء ﻷول ﻣـﺮة ﰲ دﻳﺴﻤﱪ 2024 . ﺗﻜﺸﻒ اﻟﺪراﺳﺔ أن YR4 ﻣﻦ اﻟﻨﻮع اﻟﺼﺨﺮي اﻟﺼﻠﺐ وﻣﻦ ا ـﺮﺟﺢ أﻧـﻪ ﻧﺸـﺄ ﻣـﻦ ﻋﺎﺋﻠـﺔ ﻛﻮﻳﻜﺒﺎت ﺗﻘﻊ ﰲ اﻟﺤﺰام اﻟﺮﺋـ ـ ﻴﴘ ا ﺮﻛـﺰي ﺑ ا ﺮﻳﺦ وا ﺸﱰي وﻫﻲ ﻣﻨﻄﻘﺔ ﻟﻢ ﻳﻌـﺮف ﺳﺎﺑﻘﺎ أﻧﻬﺎ ﺗ ﻨﺘﺞ ﻛﻮﻳﻜﺒـﺎت ﻋـﺎﺑﺮة ﻟـﻸرض . ﻗﺎل ﺑﺮاﻳﺲ ﺑﻮﻟ اﻟﺒﺎﺣﺚ ﰲ ﴍﻛـﺔ ﻳﻮرﻳﻜـﺎ ﺳﺎﻳﻨﺘﻴﻔﻴﻚ وا ﺆﻟﻒ اﻟﺮﺋﻴﴘ ﻟﻠﺪراﺳﺔ " : ﻳﺪور YR4 ﻔﺴﻪ ﺣﻮل ﻧ ﻣﺮة ﻛﻞ 20 دﻗﻴﻘﺔ وﻳـﺪور اﺮ ﺗ ﰲ اﺗﺠﺎه ﺟﻌﻲ وﻟﻪ ﺷـﻜﻞ ﻣﺴـﻄﺢ وﻏـ وﻛ ﻣﻨ ـﺘﻈﻢ ﺜﺎﻓ ـﺔ اﻟﺼ ـﺨﻮر اﻟﺼ ـﻠﺒﺔ ﻫ ـﻲ ﻧﻔﺴﻬﺎ ﻳ". ﻘﺪم ﻟﻨﺎ ﺷﻜ ﻞ اﻟﻜﻮﻳﻜﺐ أدﻟﺔً ﺣﻮل ﻛﻴﻔﻴﺔ ﺗﺸﻜﻠﻪ وﺳﻼﻣﺘﻪ اﻟﻬﻴﻜﻠﻴﺔ . إن ﻣﻌﺮﻓﺔ ﻫﺬه اﻟﺨﺼﺎﺋﺺ أﻣﺮ ﺑﺎﻟﻎ اﻷﻫﻤﻴﺔ ﻟﺘﺤﺪﻳﺪ ﻣﻘﺪار اﻟﺠﻬﺪ أو ﻧﻮع اﻟﺘﻘﻨﻴﺔ اﻟﻼزﻣـﺔ ﻟﺤﺮ ف ﻣﺴـﺎر اﻟﻜﻮﻳﻜـ ﺐ إذا اﻋﺘـﱪ ﺗﻬﺪﻳـﺪ . اً ــــــ ﻋﲆ اﻟﺮﻏﻢ ﻣﻦ ﻛﻮﻧـﻪ ﺳـﻴﻨﺎرﻳﻮ ﻳﻔﻜـ ﺮ ﻓﻴـﻪ ﻋﻠﻤﺎء اﻟﻔﻠﻚ وﻛ ﺘـﺎب ﻫﻮﻟﻴـﻮود ﻋـﲆ ﻧﻄـﺎق واﺳﻊ ﻟﻌﻘﻮد ﻓﻘـﺪ أﺛﺒﺘـﺖ ﻋﻤﻠﻴـﺎت اﻟﺮﺻـﺪ اﻹﺿﺎﻓﻴﺔ ﻣﻨﺬ ذﻟﻚ اﻟﺤ أن YR4 ﻟﻦ ﻳﺼﻄﺪم ﺑﺎﻷرض ﰲ ﻋﺎم 2032 ﻛﻤـﺎ ﻛـﺎن ﻣﺘﻮﻗﻌـ ﺎ ﰲ اﻷﺻﻞ وﻣﻊ ذﻟﻚ ﻫﻨـﺎك اﺣﺘﻤـﺎل ﺑﻨﺴـﺒﺔ 2% ﺎً ﺗﻘﺮﻳﺒ ﻻﺻﻄﺪاﻣﻪ ﺑﺎﻟﻘﻤﺮ . وأﺿﺎف ﺑﻮﻟ " : ﺑﻘﻄﺮ ﻳﺒﻠـﻎ ﺣـﻮاﱄ 50-60 ) اً ﻣﱰ ﻣﺎ ﻳﻌﺎدل ﻋﺮض ﻣﻠﻌﺐ ﻛﺮة ﻗﺪم ﻌـﺪ ﻳ( ﻫﺬا اﻟﻜﻮﻳﻜﺐ أﺣﺪ أﻛـﱪ ا ﻷﺟـﺮام ﰲ اﻟﺘـﺎرﻳﺦ اﻟﺤﺪﻳﺚ اﻟﺘﻲ ﻳ ﻤﻜﻦ أن ﺗﺼﻄﺪم ﺑﺎﻟﻘﻤﺮ ." إذا ﻛﺎن اﻷﻣﺮ ﻛﺬﻟﻚ ﻓﺴـﻴﺘﻴﺢ ذﻟـﻚ ﻟﻠﻌﻠﻤـﺎء ﻓﺮﺻﺔ ﻛﺒ ة ﻟﺪراﺳﺔ ﻛﻴﻔﻴـﺔ ارﺗﺒـﺎط ﺣﺠـﻢ اﻟﻜﻮﻳﻜ ﺐ ﺑﺤﺠﻢ اﻟﺤﻔﺮة اﻟﺘﻲ ﻳﺤـﺪﺛﻬﺎ وﻫـﻮ أﻣﺮ ﻟﻢ ﻧﺘﻤﻜﻦ ﻣ ﻦ ﻗﻴﺎﺳﻪ ﺑﺸﻜﻞ ﻣﺒﺎﴍ ﻣـﻦ ﻏﺎﻟﺒ . ﻗﺒﻞ ﺎ ﻣﺎ ﺗﻜﻮن اﻟﻜﻮﻳﻜﺒـﺎت اﻟﺘـﻲ ﻳﺒﻠـﻎ ﻗﻄﺮﻫﺎ 100 ﻣﱰ أو أﻛﱪ ﻣﺎ ﻳ ﻄﻠﻖ ﻋ ﻠﻴﻪ ﻋﻠﻤﺎء اﻟﻔﻠﻚ " أﻛﻮام اﻷﻧﻘﺎض " وﻫـﻲ ﺗﺘﻜـﻮن ﻣـﻦ ﺷﻈﺎﻳﺎ ﻣﻦ ﻛﻮﻳﻜﺐ رﺋﻴﴘ أﻛﱪ ﺣﺠ ﻤ ﺎ ﺗﺴﺒﺐ ﰲ اﺻﻄﺪام ﺟﺰﺋﻲ ﻣﻤﺎ ﻳﻮﻓﺮ رؤى ﻗﻴﻤﺔ ﺣﻮل دﻳﻨﺎﻣﻴﻜﻴﺎت ﺗﺸﻜﻞ اﻟﻜﻮﻳﻜﺒﺎت . ﻳﻮﻟﻴﻮ - ﺃﻏﺴﻄﺲ 2 0 2 5