Free Astronomy Magazine January-February 2024 ARABIC VERSION

Lemaître and Edwin Hubble. Ac- cording to Zwicky, the phenomenon of the reddening of light (a shifting towards longer wavelengths com- pared to those of the light just emit- ted) was attributed to the fact that on their journey towards the ob- server, the photons slowly lose en- ergy by interacting with interga- lactic and interstellar matter and with other photons. Since the en- ergy loss corresponds to a reduction in frequency (Planck’s constant, 1900), the process produces a red- shift of the spectral lines that in- creases proportionally with the distance from the source. The “tired light” hypothesis (a term coined by Richard Tolman in the early 1930s) was not the only one to interpret the redshift with the pro- gressive loss of photon energy, but it was undoubtedly the best known and best developed alternative to the model of an expanding universe. At that time, the instruments avail- able to astronomers did not allow them to establish which of the two opposing models described reality, and although over the decades the idea of an expanding universe be- came increasingly established, until at least the 1980s, tired light cos- mology had remained difficult to disprove. Indeed, some scientists had meanwhile found new argu- ments in favor of the stationary uni- verse. An example is Halton Arp (famous for his catalog of peculiar galaxies), who argued that the red- shift of quasars was not attributable to their extreme distance in an ex- panding universe, but rather to local effects of the system consid- ered. In practice, Arp asserted that quasars were objects ejected from the nuclei of very active galaxies, such as those of Seyfert. Although controversial and opposed, this hy- pothesis also contributed to keep- راﺟﻨـــــــــﺪرا ﺟﻮ ﺘـــــــــﺎ أﺳـــــــــﺘﺎذ ﻣﺴـــــــــﺎﻋﺪ ﻓـــــــــﻲ اﻟﻔ ﺎء ﺑ ﻠ ﺔ اﻟﻌﻠﻮم ﺑﺠﺎﻣﻌﺔ أوﺗﺎوا . اﻟـــــــــﺬ ــــــــﻮﻧﻲ اﻟﻬﺠـــــــــ وﻓﻘــــــــﺎ ﻟﻠﻨﻤـــــــــﻮذج اﻟ ﻃـــــــﻮرﻩ ـــــــﻮن ﺿـــــــﻌﻒﻋﻤــــــــﺮ ﺳـــــــﻴ ﻮن ﻋﻤـــــــﺮاﻟ اﻵن اﻟ ﻮن اﻟﻤﻘﺒﻮل ﺣ . ﻓـﺮ زو ﻜــﻲ ﻗﻀـﻰ ﻣﻌﻈـﻢﺣ ﺎﺗـﮫ ﻓـﻲ ــــﺚ ﻗــــﺪم ــــﺎ ﺣ ــــﺎ ﻟﻠﺘﻜﻨﻮﻟﻮﺟ ﻣﻌﻬــــﺪ ﺎﻟ ﻔﻮر اﻟﻌﺪ ﺪ ﻣﻦ اﻟﻤﺴـﺎﻫﻤﺎت اﻟﻤﻬﻤـﺔ ﻓـﻲﻋﻠـﻢ ـﮫ أﺑـﻮة و ﻨﺴـﺐ إﻟ اﻟﻔﻠﻚ اﻟﻨﻈﺮي واﻟﺮﺻـﺪ " ﻣﻔﻬﻮم اﻟﻨﻮراﻟﻤﺘﻌﺐ ." ﻫﺎﻟﺘﻮن آر ﻟـ أﺣﺪ أﺷﺪ اﻟﻤﻌﺎرﺿ ـ ﻤﻴﻊ ــــﻮن اﻟﻤﺘﻮﺳــــﻊ ﻧﻤــــﺎذج اﻟ . وﻗــــﺎل إن اﻻﻧﺰ ــــﺎح ــﺔ ﻧﺤـﻮ اﻷ ﻤـﺮﻟـﻢ ﻜـﻦ ﻧﺘﻴﺠـﺔ ﻟﻠﺤﺮﻛـﺔ اﻟﻔ ﺎﺋ ـــــﻮن ﻟـــــﮫ ﻟﻸﺟـــــﺮام اﻟﺴـــــﻤﺎو ﺔ، ﺑـــــﻞ ﻳﺠـــــﺐ أن ﻳ ــﻮﻧﻲ أو أﺻـﻞ ﻏــ " " ﺟــﻮﻫﺮي وﻗـﺪ ﻋﺎرﺿـﺖ رؤ ﺘـــــــــــﮫ اﻟ ﺪ ﻠـــــــــــﺔ ﻧﻤـــــــــــﻮذج اﻻﻧﻔﺠـــــــــــﺎراﻟﻜﺒـــــــــــ اﻟﻘ ﺎﺳﻲ ﻟﻌﻘﻮد ﻣﻦ اﻟﺰﻣﻦ . ووﻓﻘﺎ ﻟﺰوﻳﻜﻲ ﻓﺈن ﻇﺎﻫﺮة اﺣﻤﺮار اﻟﻀـﻮء ) اﻟﺘﺤﻮل ﻧﺤ ﻮ أﻃﻮال ﻣﻮﺟﻴﺔ أﻃﻮل ﻣﻘﺎرﻧـﺔ ﺑﺄﻃﻮال ﻣﻮﺟﻴﺔ اﻟﻀﻮء ا ﻨﺒﻌﺚ ﻟﻠﺘﻮ ( ﺗﻌـﺰى إﱃ ﺣﻘﻴﻘـﺔ أن اﻟﻔﻮﺗﻮﻧـﺎت ﺗﻔﻘـﺪ ﻃﺎﻗﺘﻬـﺎ ﺑﺒﻂء أﺛﻨﺎء رﺣﻠﺘﻬﺎ ﻧﺤﻮ اﻟﺮاﺻﺪ، ﻣﻦ ﺧـﻼل اﻟﺘﻔﺎﻋﻞ ﻣﻊ اﻟﻨﺠﻮم ا ﻮﺟﻮدة ﺑ ا ﺠـﺮات . وا ﺎدة ﺑ اﻟﻨﺠﻮم وﻣﻊ اﻟﻔﻮﺗﻮﻧﺎت اﻷﺧﺮى . وﺑﻤﺎ أن ﻓﻘﺪان اﻟﻄﺎﻗﺔ ﻳﺘﻮاﻓﻖ ﻣﻊ اﻧﺨﻔﺎض ) ﰲ اﻟﱰدد ﺛﺎﺑﺖ ﺑﻼﻧﻚ، 1900 ( ﻓﺈن اﻟﻌﻤﻠﻴـﺔ ﺗﻨﺘﺞ اﻧﺰﻳﺎﺣًﺎ أﺣﻤﺮ ﻟﻠﺨﻄﻮط اﻟﻄﻴﻔﻴﺔ ﻳﺰداد ﺑﺸﻜﻞ ﻣﺘﻨﺎﺳﺐ ﻣﻊ ا ﺴﺎﻓﺔ ﻣﻦ ا ﺼﺪر ﻟﻢ . ﺗﻜ ـﻦ ﻓﺮﺿـﻴﺔ » اﻟﻀـﻮء ا ﺘﻌــﺐ «) وﻫ ـﻮ ﻣﺼﻄﻠﺢ ﺻـﺎﻏﻪ رﻳﺘﺸـﺎرد ﺗﻮ ـﺎن أواﺋـﻞ ﺛﻼﺛﻴﻨﻴﺎت اﻟﻘﺮن اﻟﻌ ( ﴩﻳﻦ ـ ﻫـﻲ اﻟﻮﺣﻴـﺪة اﻟﺘﻲ ﺗﻔ ـ ﴪ اﻻﻧﺰﻳـﺎح اﻷﺣﻤـﺮ ﻣـﻊ اﻟﻔﻘـﺪ ـــ ــ اﻟﺘﺪرﻳﺠﻲ ﻟﻄﺎﻗﺔ اﻟﻔﻮﺗﻮن ﻟﻜﻨﻪ ﻛﺎن ﺑﻼ ﺷﻚ اﻟﺒﺪﻳﻞ اﻷﻛﺜﺮ ﺷﻬﺮة واﻷﻓﻀﻞ ﺗﻄﻮر اً ﻟﻨﻤﻮذج اﻟﻜﻮن ا ﺘﻮﺳﻊ . ﰲ ذﻟﻚ اﻟﻮﻗﺖ ﻟـﻢ ﺗﺴـﻤﺢ اﻷدوات ا ﺘﺎﺣـﺔ ﻟﻌﻠﻤﺎء اﻟﻔﻠﻚ ﺑﺘﺤﺪﻳـﺪ أي ﻣـﻦ اﻟﻨﻤـﻮذﺟ ا ﺘﻌﺎرﺿ ﻳ ﺼﻒ اﻟﻮاﻗﻊ، وﻋﲆ اﻟﺮﻏﻢ ﻣـﻦ أﻧﻪ ﻋﲆ ﻣﺮ اﻟﻌﻘﻮد أﺻﺒﺤﺖ ﻓﻜـﺮة اﻟﻜـﻮن ا ﺘﻮﺳــﻊ راﺳــﺨﺔ ﺑﺸـﻜﻞ ﻣﺘﺰاﻳـﺪ، ﺣﺘـﻰ اﻟﺜﻤﺎﻧﻴﻨﻴﺎت ﻋﲆ اﻷﻗﻞ . ﻟﻘﺪ ﻇﻞ ﻋﻠﻢ اﻟﻜﻮﻧ ﻴﺎت اﻟﻀﻮﺋﻲ ا ﺘﻌﺐ ﻣـﻦ اﻟﺼـﻌﺐ دﺣﻀـﻪ ، ﰲ اﻟﻮاﻗـﻊ وﺟـﺪ ﺑﻌــﺾ اﻟﻌﻠﻤﺎء ﰲ ﻫﺬه اﻷﺛﻨﺎء ﺣﺠﺠًﺎ ﺟﺪﻳﺪة ﻟﺼﺎﻟﺢ اﻟﻜﻮن اﻟﺜﺎﺑﺖ وﻣﻦ اﻷﻣﺜﻠﺔ ﻋﲆ ذﻟﻚ ﻫﺎﻟﺘﻮن آرب ) ا ﺸﻬﻮر ﺑﺘﺼﻨﻴﻔﻪ ﻟﻠﻤﺠﺮات اﻟﻐﺮﻳﺒﺔ ( اﻟﺬي ﺟﺎدل ﺑﺄن اﻻﻧﺰﻳﺎح اﻷﺣﻤﺮ ﻟﻠﻜﻮازارات ـــ ﻻ ﻳُﻌﺰى إﱃ ا ﺴﺎﻓﺔ اﻟﻘﺼﻮى اﻟﺘﻲ ﺗﻔﺼﻠ ﻬﺎ ﰲ اﻟﻜﻮن ا ﺘﻮﺳﻊ ﺑﻞ إﱃ اﻟﺘـﺄﺛ ات ا ﺤﻠﻴـﺔ ﻟﻠﻨﻈﺎم ﻗﻴﺪ اﻟﻨﻈﺮ . ﻣﻦ اﻟﻨﺎﺣﻴﺔ اﻟﻌﻤﻠﻴـﺔ، أﻛـﺪ آرب أن اﻟﻨﺠـﻮم اﻟﺰاﺋﻔﺔ ﻛﺎﻧﺖ ﻋﺒﺎرة ﻋﻦ أﺟﺴﺎم ﺗﻢ إﺧﺮاﺟ ﻬﺎ ﻣﻦ ﻧﻮى ا ﺠﺮات اﻟﻨﺸﻄﺔ ﻟﻠﻐﺎﻳﺔ ﻣﺜﻞ ﻣﺠﺮة . ﺳﻴﻔﺮت ﻋﲆ اﻟﺮﻏ ﻢ ﻣﻦ أﻧﻬﺎ ﻣﺜ ة ﻟﻠﺠـﺪل وا ﻌﺎرﺿﺔ إﻻ أن ﻫﺬه اﻟﻔﺮﺿـﻴﺔ ﺳـﺎﻫﻤﺖ ﻣﺠﻠﺔ FreeAstronomy ﺎﻟﻌﺮ ﺔ - ﻳﻨﺎﻳﺮ ﻓﺒﺮﺍﻳﺮ 2 0 2 4 7