البحث عن ذكاء خارج الأرض: الفرق بين النسختين

وحتى الآن لم نعثر على أثر يدل على وجود "ذكاء " (مخلوقات عاقلة) خارج الأرض ، تكون على درجة من الذكاء في أن ترسل أو تستقبل إشارات لاسلكية . <ref>Carl Sagan: ''On the detectivity of advanced galactic civilizations.'' Icarus, Vol. 19, Issue 3, Juli 1973, S. 350–352, {{doi|10.1016/0019-1035(73)90112-7}} [http://adsabs.harvard.edu//abs/1973Icar...19..350S @nasa ads]; William I. Newman, et al.:''Galactic civilizations - Population dynamics and interstellar diffusion'' Icarus, vol. 46, Juni 1981, S.293-327, [http://naca.larc.nasa.gov/search.jsp?R=19790011801&qs=N=4294129240+4294963769 abstract]@naca.larc.nasa.gov; J. G. Kreifeldt: A Formulation for the Number of Communicative Civilizations in the Galaxy; Icarus, vol. 14, S. 419 [http://adsabs.harvard.edu//abs/1971Icar...14..419K @nasa ads] {{Webarchive|url=http://web.archive.org/web/20160306071420/http://naca.larc.nasa.gov/search.jsp?R=19790011801&qs=N%3D4294129240%2B4294963769 |date=06 مارس 2016}}</ref><ref>Frank J. Tipler: ''Extraterrestrial Intelligence - A Skeptical View of Radio Searches.'' Science 14. Januar 1983, Vol. 219 no. 4581, S. 110–112, {{DOI|10.1126/science.219.4581.110-a}}; [http://www.sciencemag.org/content/219/4581/110.1.short preview]; [http://adsabs.harvard.edu//abs/1986inns.iafcR....F B. Finney: The impact of contact]Abstract@nasa ads abgerufen am 16. März 2011 {{Webarchive|url=http://web.archive.org/web/20150924143409/http://www.sciencemag.org/content/219/4581/110.1.short |date=24 سبتمبر 2015}}</ref>

.<ref>[http://news.bbc.co.uk/2/hi/7870562.stm Number of alien worlds quantified] bbc.co.uk, 5. Februar 2009; [http://www.newscientist.com/blogs/shortsharpscience/2009/02/how-many-intelligent-civilisat.html How many intelligent civilisations are in our galaxy?] 5. Februar 2009, abgerufen am 5. März 2011 {{Webarchive|url=http://web.archive.org/web/20171027184037/http://news.bbc.co.uk/2/hi/7870562.stm |date=27 أكتوبر 2017}}</ref><ref>D. H. Forgan: ''A numerical testbed for hypotheses of extraterrestrial life and intelligence.'' International Journal of Astrobiology, Vol. 8, Issue 2, S. 121–131, April 2009 [http://adsabs.harvard.edu//abs/2009IJAsB...8..121F Abstract@NASA ADS], [[:arxiv:0810.2222|@arxiv]] abgerufen am 5. März 2011</ref>

كما قام "ستيفن دول" في عام 1964 بدراسة لتقدير لاحتمال وجود عدد من كواكب يتصف بكونة صالح لوجود حياة في مجرة درب التبانة . <ref>Stephen H. Dole, Isaac Asimov: Planets for man - based on the RAND Corporation Research Study, Habitable planets for man. Random House, New York, 1964; Claudio Maccone: ''Mathematical SETI - statistics, signal processing, space missions.'' Springer, Berlin 2012, ISBN 978-3-642-27436-7, S.111-119 [http://books.google.at/books?id=cuJMzvdIWMcC&pg=PA111&dq=how+many+planets+for+man+and+aliens+maccone+seti&hl=de&sa=X&ei=ChhTUc6qOo_PsgaGxIGwDQ&redir_esc=y#v=onepage&q=how%20many%20planets%20for%20man%20and%20aliens%20maccone%20seti&f=false @google books] {{Webarchive|url=http://web.archive.org/web/20171027231903/https://books.google.at/books?id=cuJMzvdIWMcC&pg=PA111&dq=how+many+planets+for+man+and+aliens+maccone+seti&hl=de&sa=X&ei=ChhTUc6qOo_PsgaGxIGwDQ&redir_esc=y |date=27 أكتوبر 2017}}</ref>

<ref>[http://web.archive.org/web/20100425081435/http://seds.lpl.arizona.edu/Messier/more/mw.html The Milky Way Galaxy] seds.lpl.arizona.edu@web.archive.org; [http://www.universetoday.com/guide-to-space/milky-way/how-many-stars-are-in-the-milky-way/ How Many Stars are in the Milky Way?] www.universetoday.com {{Webarchive|url=http://web.archive.org/web/20100502073142/http://www.universetoday.com:80/guide-to-space/milky-way/how-many-stars-are-in-the-milky-way/ |date=02 مايو 2010}}</ref><ref>[http://www.zeit.de/news-022011/20/iptc-bdt-20110220-395-28833736xml «Kepler»-Mission: 50 Milliarden Planeten in Milchstraße] zeit.de, 20. Februar 2011; [http://www.spiegel.de/wissenschaft/weltall/0,1518,746624,00.html Astronomen vermuten 50 Milliarden Planeten in Milchstraße] spiegel.de, 20. Februar 2011, abgerufen am 5. März 2011 {{Webarchive|url=http://web.archive.org/web/20171027231555/http://www.zeit.de/news-022011/20/iptc-bdt-20110220-395-28833736xml |date=27 أكتوبر 2017}}</ref><ref>[http://www.wired.co.uk/news/archive/2011-02/21/kepler-galaxy-census Kepler’s galaxy census estimates 50 billion planets] wired.co.uk, 21. Februar 2011; [http://derstandard.at/1297818573637/50-Milliarden-Planeten-allein-in-unserer-Milchstraße 50 Milliarden Planeten allein in unserer Milchstraße] derstandard.at, 21. Februar 2011, abgerufen am 5. März 2011</ref>

<ref>[http://www.daviddarling.info/encyclopedia/C/carbon-based_life.html carbon-based life] daviddarling.info {{Webarchive|url=http://web.archive.org/web/20170402233539/http://www.daviddarling.info/encyclopedia/C/carbon-based_life.html |date=02 أبريل 2017}}</ref> كما يمكن افتراض نوع من الحياة آخر قائم على كيمياء [[السيليكون]] ، ولكن لـ[[الكربون]] تعددية أكبر في تكوين [[جزيئات]] مستقرة و شبه مستقرة .

<ref>[http://www.pnas.org/content/98/3/805.full.pdf Norman R. Pace: The universal nature of biochemistry] (PDF; 83&nbsp;kB) pnas.org; [http://www.daviddarling.info/encyclopedia/S/siliconlife.html silicon-based life]daviddarling.info; [[:en:Hypothetical types of biochemistry|Hypothetical types of biochemistry]] en.wikipedia, abgerufen am 15. März 2011 {{Webarchive|url=http://web.archive.org/web/20160910044531/http://www.pnas.org:80/content/98/3/805.full.pdf |date=10 سبتمبر 2016}}</ref><ref>William Bains: ''Many Chemistries Could Be Used to Build Living Systems.'' Astrobiology,.Volume: 4 Issue 2: September 3, 2004, doi:10.1089/153110704323175124, [http://www.ifa.hawaii.edu/~meech/a281/handouts/Baines_astrobio04.pdf pdf] @ifa.hawaii.edu, abgerufen am 30.September 2013 {{Webarchive|url=http://web.archive.org/web/20170622114129/http://www.ifa.hawaii.edu:80/~meech/a281/handouts/Baines_astrobio04.pdf |date=22 يونيو 2017}}</ref>

<ref>Wiliam Edmondson: Understanding the Search Space for SETI.S.223-234, in: Vakoch, 2011, [http://books.google.at/books?id=4oxZgRn3QFYC&pg=PA223&lpg=PA223&dq=understanding+the+search+space+for+seti&source=bl&ots=EnGE-hvRbr&sig=4b89iGOenhOISRAYEOTZmm4OQwg&hl=en&sa=X&ei=bAl9UJPTMcOk4gT564CwAQ&ved=0CCwQ6AEwAA#v=onepage&q=understanding%20the%20search%20space%20for%20seti&f=false]@google books, abgerufen am 16.Oktober 2012 {{Webarchive|url=http://web.archive.org/web/20140226162801/http://books.google.at/books?id=4oxZgRn3QFYC&pg=PA223&lpg=PA223&dq=understanding+the+search+space+for+seti&source=bl&ots=EnGE-hvRbr&sig=4b89iGOenhOISRAYEOTZmm4OQwg&hl=en&sa=X&ei=bAl9UJPTMcOk4gT564CwAQ&ved=0CCwQ6AEwAA |date=26 فبراير 2014}}</ref>