Free Astronomy Magazine March-April 2023 ARABIC VERSION

Considering the vastness of the Milky Way, even a thousand uniformly distributed techno- logical civilizations would be considered “relatively few” be- cause it would mean that there are, on average, one for every 200-300 million stars and, on average, they are far enough away from each other as to make any attempt at “physical contact” impossible. Perhaps, however, electromagnetic sig- nals are not too distant to ex- change, either intentionally or casually. Even if only a tenth of those civilizations routinely sent signals of various kinds into space powerful enough to be discernible hundreds or thousands of light-years away, the chances of registering them with SETI programs would not be entirely negligible. But that has never happened. Why? Several solutions have been proposed to this aspect of the Fermi paradox: perhaps we don’t know which specific wavelengths to tune into, or we don’t “listen” for long enough, or we still don’t know where to point our instru- ments. There could also be forms of communication that we do not know of, or there simply are no alien signals trav- eling in the galaxy, at least not in our direction. Regardless of assessments made by any aliens, intentionally sending messages to specific targets requires some energy, and unless this is available in unlimited quantities, it is likely that any aliens will also have to select the most promising targets. From anywhere in our galaxy, a civilization analyzing our planet’s atmosphere could at best establish that there is life here, although without un- How likely is extraterrestrial life? What does existing scientific knowledge about physics, chem- istry, meteorology and biology tell us about the likelihood of extraterrestrial life and civilizations? And what does the fact that there is currently no credible scientific evidence for the existence of extraterrestrial biospheres or civilizations teach us? This book reviews the various scientific issues that arise in considering the question of how common extraterrestrial life is likely to be in our galaxy and whether humans are likely to detect it. Are we being watched? — The search for life in the cosmos There is no more fascinating question than whether or not we are alone in a vast universe. Here, Paul Murdin applies the lat- est scientific discoveries and theories to inquire whether life exists on other planets and, if so, what forms it might take. Life as we do not know it For the past twenty years, Peter Ward has been at the forefront of popular science writing, with books such as the influential and controversial Rare Earth. In Life as We Do Not Know It, Ward, with his signature blend of eloquence, humor, and learned insight, vividly details the latest scientific findings, cut- ting-edge research, and intrepid new theories on the subject of alien life and the possible extraterrestrial origins of life on Earth. In lucid, entertaining, and bold prose, Peter Ward once again challenges our notions of life on earth (and beyond). Signatures of life — Science searches the Universe Are we alone in the universe, or is life a universal phenomenon? For decades, astronomers in SETI have scanned the Universe for intelligent signals, but with no success. In this intriguing book, Edward Ashpole explains the probable reasons for this and dis- cusses other avenues of investigation more in line with the nature Could there be somewhere life as advanced as here on Earth, or are we more likely to find primitive life-forms? Or are we the sole living organisms in a desolate and boundless cosmos? Professor Murdin invites us to join him in exploring an extraor- dinary array of evidence to determine if there is life elsewhere in the cosmos. of science and technology. The author examines the problems in- herent in scanning the universe for radio or optical signals from alien intelligence. These include the difficulty of trying to commu- nicate with another species possessing a completely unknown form of technology, and the vast distances that alien communica- tions would have to travel to reach us. ﻣﺠﻠﺔ Astronomy ﺎﻟﻌﺮ ﺔ ﺑﺎﻟﻨﻈﺮ إﱃ اﺗﺴـﺎع ﻣﺠـﺮة درب اﻟﺘﺒﺎﻧـﺔ ﻳﻤﻜﻦ اﻋﺘﺒﺎر ﺣﺘﻰ أﻟﻒ ﺣﻀﺎرة ﺗﻘﻨﻴـﺔ ﻣﻮزﻋﺔ ﺑﺸﻜﻞ ﻣﻮﺣﺪ " ﻗﻠﻴﻠﺔ ﻧﺴﺒﻴًﺎ ﻷن " ﻳﻌﻨ ذﻟﻚ ﻲ أن ﻫﻨﺎك ﰲ ا ﺘﻮﺳﻂ ﺣﻀﺎرة واﺣﺪة ﻟﻜﻞ ٢٠٠ - ٣٠٠ ﻣﻠﻴﻮن ﻧﺠـﻢ وﰲ ا ﺘﻮﺳﻂ ﻫﻲ ﺑﻌﻴﺪة ﻋـﻦ ﺑﻌﻀـﻬﺎ ﺑﻤـﺎ ﻳﻜﻔـﻲ ﻟﺠﻌـﻞ أي ﻣﺤﺎوﻟـﺔ ﻟ" ﻼﺗﺼـﺎل اﻟﺠﺴﺪي ، ﺴﺘﺤﻴﻠﺔ ﻣ" وﻣﻊ ذﻟﻚ رﺑﻤـﺎ ﻻ ﺗﻜـﻮن اﻹﺷـﺎرات اﻟﻜﻬﺮوﻣﻐﻨﺎﻃﻴﺴـﻴﺔ ﺑ ﻌﻴﺪة ﺟـﺪًا ﺑﺤﻴـﺚ ﻻ ﻳﻤﻜـﻦ ﺗﻐﻴ ﻫـﺎ ﺳﻮاء ﻋﻦ ﻗﺼﺪ أو ﻋﺮﺿًﺎ ﺣﺘﻰ ﻟﻮ أرﺳﻞ ﻋُﴩ ﺗﻠﻚ اﻟﺤﻀـﺎرات ﺑﺸـﻜﻞ روﺗﻴﻨـﻲ إﺷﺎرات ﻣﻦ أﻧﻮاع ﻣﺨﺘﻠﻔﺔ إﱃ اﻟﻔﻀـﺎء ﺑﻘﻮة ﻛﺎﻓﻴﺔ ﺑﺤﻴﺚ ﻳﻤﻜﻦ ﺗﻤﻴﻴﺰﻫﺎ ﻋـﲆ ﺑﻌ ﺪ ﻣﺌﺎت أو آﻻف اﻟﺴﻨ اﻟﻀﻮﺋﻴﺔ ﻓﺈن ﻓﺮص ﺗﺴﺠﻴﻠﻬﺎ ﰲ ﺑﺮاﻣﺞ ( ﺳﻴﺘﻲ ) ﻟـﻦ ﺗﻜﻮن ﺿﺌﻴﻠﺔ ﺗﻤﺎﻣًﺎ ﻟﻜﻦ ﻫﺬا ﻟﻢ ﻳﺤـﺪث أﺑﺪا ﺎذا؟ ﺗﻢ اﻗﱰاح اﻟﻌﺪﻳﺪ ﻣﻦ اﻟﺤﻠﻮل ﻟﻬﺬا اﻟﺠﺎﻧﺐ ﻣﻦ ﻣﻔﺎرﻗﺔ ﻓ : ﻣﻲ رﺑﻤـﺎ ﻻ ﻧﻌﺮف اﻷﻃﻮال ا ﻮﺟﻴﺔ ا ﺤﺪدة اﻟﺘـﻲ ﻳﺠـﺐ ﺿـﺒﻄﻬﺎ أو أﻧﻨـﺎ ﻻ " ﻧﺴـﺘﻤﻊ " ﻟﻔﱰة ﻛﺎﻓﻴﺔ أو ﻣﺎ زﻟﻨﺎ ﻻ ﻧﻌﺮف إﱃ أﻳـﻦ ﻧﺘﻮﺟﻪ ﻟﻠﺒﺤﺚ ، ﺷﺎرات ﻋﻦ إ ﻗـﺪ ﺗﻜـﻮن ﻫﻨـﺎك أﻳ ﻀًـﺎ أﺷـﻜﺎل ﻣـﻦ اﻻﺗﺼـﺎل ﻻ ﻧﻌﺮﻓﻬﺎ أو ﺑﺒﺴـﺎﻃﺔ ﻻ ﺗﻮﺟـﺪ إﺷـﺎرات ﻏﺮﻳﺒﺔ ﺗﺠﺘﺎز ا ﺠﺮة ﻋﲆ اﻷﻗﻞ ﻟـﻴﺲ ﰲ اﺗﺠﺎﻫﻨﺎ ، ﺑﻐﺾ اﻟﻨﻈﺮ ﻋـﻦ اﻟﺘﻘﻴﻴ ﻤـﺎت اﻟﺘﻲ أﺟﺮاﻫﺎ أي ﻣﺨﻠﻮق ﻓﻀـﺎﺋﻲ ﻓـﺈن إرﺳﺎل اﻟﺮﺳﺎﺋﻞ ﻋـﻦ ﻗﺼـﺪ إﱃ أﻫـﺪاف ﻣﺤﺪدة ﻳﺘﻄﻠﺐ ﺑﻌﺾ اﻟﻄﺎﻗﺔ وﻣـﺎ ﻟـﻢ ﻳﻜﻦ ذﻟﻚ ﻣﺘﺎﺣًﺎ ﺑﻜﻤﻴﺎت ﻏ ﻣﺤـﺪودة ﻓﻤ ـﻦ ا ﺤﺘﻤ ـﻞ أن ﻳﻀ ـﻄﺮ أي ﻛ ـﺎﺋﻦ ﻓﻀﺎﺋﻲ أﻳﻀًﺎ إﱃ ﺗﺤﺪﻳﺪ اﻷﻫﺪاف ا ﺜﺎﻟﻴﺔ . ﻣﻦ أي ﻣﻜﺎن ﰲ ﻣﺠﺮﺗﻨﺎ ﻳﻤﻜﻦ ﻟﻠﺤﻀﺎرة اﻟﺘﻲ ﺗﺤﻠﻞ اﻟﻐﻼف اﻟﺠـﻮي ﻟﻜﻮﻛﺒﻨـﺎ أن ﺗﺜﺒﺖ ﰲ أﻓﻀﻞ اﻷﺣﻮال وﺟﻮد ﺣﻴﺎة ﻫﻨـﺎ ﻋﲆ اﻟﺮﻏﻢ ﻣﻦ ﻋﺪم ﻓﻬﻢ ﻣﺎ ﻫﻲ ﻣﺮﺣﻠﺔ اﻟﺘﻄﻮر . ـاﻟ ﺤ ﺎة ﻤﺎ ﻻ ﻧﻌﺮﻓﻬﺎ ﺧـــﻼل ـــ وارد ﻓــــﻲﻃﻠ ﻌــــﺔ ــــﺎن ﺑ اﻟﻌﺸــــﺮ ﻦ ﻋﺎﻣًـــﺎ اﻟﻤﺎﺿــــ ﺔ ، ــــﺎت اﻟﻌﻠــــﻮم اﻟﺸــــﻌﺒ ﺔ ، ﻣــــﻊ ﻛﺘــــﺐﻣﺜــــﻞ ﻛﺘﺎ " اﻷرضاﻟﻨــــﺎدرة " اﻟﻤـﺆﺛﺮة واﻟﻤﺜــ ة ﻟﻠﺠــﺪل . ـ ﻓــﻲ اﻟــ ﺤ ﺎة ﻤـﺎ ﻻ ﻧﻌﺮﻓﻬــﺎ ، ﻘــﺪم وارد ، ﻤﺰ ﺞ ﻣﻤ ﻣﻦ اﻟ ﻼﻏﺔ واﻟﻔ ﺎﻫﺔ واﻟ ﺼ ة اﻟﻤ ﻜﺘﺴ ﺔ ــــــﺔ واﻟﺒﺤــــــﻮث ﺗﻔﺎﺻــــــﻴﻞ واﺿــــــﺤﺔ ﻷﺣــــــﺪث اﻻﻛﺘﺸــــــﺎﻓﺎت اﻟﻌﻠﻤ اﻟﻤﺘﻄـﻮرة واﻟﻨﻈﺮ ـﺎت اﻟــ ـ ـ ﺠﺪ ﺪة اﻟـ ﺠﺮ ﺌﺔ ﺣــﻮل ﻣﻮﺿــﻮع اﻟــ ـ ﺤ ﺎة ـــــﺎة اﻟﻔﻀــــﺎﺋ ﺔ و اﻷﺻـــــﻮل اﻟﻤﺤﺘﻤﻠـــــﺔ ﺧـــــﺎرج ﻮﻛـــــﺐ اﻷرض ﻟﻠﺤ ﻋﻠـــــﻰ اﻷرض . ـــــ وارد ﻣـــــﺮة أﺧـــــﺮىﻣﻔﺎﻫ ﻤﻨـــــﺎ ﻋـــــﻦ ﺑ ﺘﺤـــــﺪ ـاﻟ ﺤ ﺎة ﻋﻠﻰ اﻷرض وﻣﺎ ﻌﺪﻫﺎ . اﺣﺘﻤﺎﻟ ﺔ وﺟﻮد ﺣ ﺎة ﺧﺎرج ﻮﻛﺐ اﻷرض؟ ﻣﺎ ﻣﺪ ـﺔ اﻟـ ـﺎ اﻟﻤﻌﺮﻓـﺔ اﻟﻌﻠﻤ ﻣـﺎذا ﺗﺨ ـ ــﺎء ـﺎء واﻟﻜ ﻤ ﺤﺎﻟ ﺔ ﻋـﻦ اﻟﻔ واﻷرﺻـــــﺎد اﻟــــــ ـ ـــــﺎ ﻋــــــﻦ اﺣﺘﻤ ﺠﻮ ﺔ واﻟﺒﻴﻮﻟﻮﺟ ــــــﺎة ـــــﺔ وﺟــــــﻮد ﺣ ﺎﻟ وﺣﻀــﺎراتﺧــﺎرج ﻮﻛــﺐ اﻷرض؟ وﻣــﺎذا ﺗﻌﻠﻤﻨــﺎ ﺣﻘ ﻘــﺔ أﻧــﮫ ﻻ ـﮫ ﻟﻮﺟـﻮد اﻟﻤﺤـ ﻂ اﻟـ ﻳﻮﺟﺪ ﺣﺎﻟ ًﺎ دﻟﻴـﻞ ﻋﻠﻤـﻲﻣﻮﺛـﻮق ـ ﺤﻴﻮي أو اﻟــــ ـ ﺤﻀﺎراتﺧـــــﺎرج ﻮﻛــــﺐ اﻷرض؟ ﺴـــــﺘﻌﺮضﻫــــﺬا اﻟﻜﺘـــــﺎب ﺗﻨﺸــﺄ ﻋﻨـﺪ اﻟﻨﻈـﺮ ﻓـﻲﻣﺴــﺄﻟﺔ ـﺔ اﻟﻤﺨﺘﻠﻔـﺔ اﻟـ اﻟﻘﻀـﺎ ﺎ اﻟﻌﻠﻤ ﺷــــﻴﻮع اﻟـــ ﻣـــﺪ ـ ﺤ ﺎة ﺧــــﺎرج ﻮﻛــــﺐ اﻷرضﻋﻠـــﻰ ــــﺢ ﻓــــﻲ اﻷرﺟ ﻣﺠﺮﻨﺎ وﻣﺎ إذا ﺎن ﻣﻦ اﻟﻤﺮﺟﺢ أن ﻜﺘﺸﻔﻬﺎ اﻟ ﺸﺮ . ﺗﻮاﻗﻴﻊ اﻟ ـ اﻟﻌ – ﺤ ﺎة ﻠﻢ ﻳﺒﺤﺚ ﻓﻲ اﻟ ﻮن ﻫﻞ ﻧﺤﻦ وﺣﺪﻧﺎ ﻓﻲ اﻟ ﻮن أم أن اﻟ ـ ﺤ ﺎة ﻇﺎﻫﺮة ﻮﻧ ﺔ ؟ ﻋﻠﻰ ﻋﻘـﻮد ، ﻗــﺎم ﻋﻠﻤـﺎء اﻟﻔﻠــﻚ ﻓـﻲ ﻣـﺪ ﻣﺸـﺮوع ﺳـ ﻤﺴــﺢ ـــﺔ ، وﻟﻜـــﻦ دون ﻧﺠـــﺎح ـــﻮن ﺑﺤﺜًـــﺎ ﻋـــﻦ إﺷـــﺎرات ذﻛ اﻟ . ﻓـــﻲﻫـــﺬا اﻟﻜﺘــــــﺎب اﻟﻤﺜــــــ ﻟﻼﻫﺘﻤــــــﺎم ، ﺸــــــﺮح إدوارد أﺷــــــﺒﻮل اﻷﺳــــــ ﺎب اﻟﻤﺤﺘﻤﻠﺔ ﻟﺬﻟﻚ و ﻨﺎﻗﺶﻃﺮﻗًﺎ أﺧﺮى ﻟﻠﺘﺤﻘ ﻴﻖ ﺗﺘﻤﺎﺷـﻰ أﻛـ ـﺎ ﻣﻊ ﻃﺒ ﻌﺔ اﻟﻌﻠﻢ واﻟﺘﻜﻨﻮﻟﻮﺟ . ﻔﺤـﺺ اﻟﻤﺆﻟـﻒ اﻟﻤﺸـ ﻼت اﻟﻤﻮﺟﻮدة ﻓﻲﻣﺴﺢ اﻟ ﻮن ﺑﺤﺜًﺎ ﻋﻦ إﺷﺎرات رادﻳﻮ أو ﺿﻮﺋ ﺔ ﻣﻦ ﻗﺎدﻣﺔ ﻣﺨﻠﻮﻗﺎت ﺔذﻛ . ﺔ ﻓﻀﺎﺋ ﻫﻞ ﻧﺤﻦ ﻣﺮاﻗﺒﻮن؟ اﻟﺒ - ﺤﺚ ﻋﻦ اﻟ ـ ﺤ ﺎة ﻓﻲ اﻟ ﻮن ﻫﻞ ﻧﺤﻦ وﺣﺪﻧﺎ ﻓﻲ اﻟ ﻮن أم أن اﻟ ـ ﺤ ﺎة ﻇﺎﻫﺮة ﻮﻧ ﺔ ؟ ﻋﻠﻰ ﻋﻘـﻮد ، ﻗــﺎم ﻋﻠﻤـﺎء اﻟﻔﻠــﻚ ﻓـﻲ ﻣـﺪ ﻣﺸـﺮوع ﺳـ ﻤﺴــﺢ ـــﺔ ، وﻟﻜـــﻦ دون ﻧﺠـــﺎح ـــﻮن ﺑﺤﺜًـــﺎ ﻋـــﻦ إﺷـــﺎرات ذﻛ اﻟ . ﻓـــﻲﻫـــﺬا اﻟﻜ ﺘــــــﺎب اﻟﻤﺜــــــ ﻟﻼﻫﺘﻤــــــﺎم ، ﺸــــــﺮح إدوارد أﺷــــــﺒﻮل اﻷﺳــــــ ﺎب اﻟﻤﺤﺘﻤﻠﺔ ﻟﺬﻟﻚ و ﻨﺎﻗﺶﻃﺮﻗًﺎ أﺧﺮى ﻟﻠﺘﺤﻘﻴﻖ ﺗﺘﻤﺎﺷـﻰ أﻛـ ـﺎ ﻣﻊ ﻃﺒ ﻌﺔ اﻟﻌﻠﻢ واﻟﺘﻜﻨﻮﻟﻮﺟ . ﻔﺤـﺺ اﻟﻤﺆﻟـﻒ اﻟﻤﺸـ ﻼت اﻟﻤﻮﺟﻮدة ﻓﻲﻣﺴﺢ اﻟ ﻮن ﺑﺤﺜًﺎ ﻋﻦ إﺷﺎرات رادﻳﻮ أو ﺿﻮﺋ ﺔ ﻣﻦ ﻗﺎدﻣﺔ ﻣﺨﻠﻮﻗﺎت ﺔذﻛ . ﺔ ﻓﻀﺎﺋ