Glaubt ihr, dass es Außerirdische gibt?
16.04.2016 um 19:59Anzeige
continuum schrieb:Und das erhöht einfach die Möglichkeit, auch wenn es sich im Bereich 0.00001% wäre.Ich vermute konkrete Mengenangaben im grenznahen ppm-Bereich irritieren den Ein oder Anderen in ihrer mathematischen Bedeutung und führen die Diskussion am Ende nur zu differentiellen Invarianten regulärer Algebren oder sonstigen Nebendiskussionen.
efficiencer schrieb:Wenn man etwas gelernt hat, dann doch das Leben sich öfter mal einen überraschenden Weg bahnt.Ja, bereits bestehendes Leben. Das hat ja auch Zeit und Möglichkeiten zu experimentieren, ob es nicht auch unter anderen, gar extremen Bedingungen existieren kann. Das läßt sich nicht auf erst entstehendes Leben übertragen.
JoschiX schrieb:Weil wir bisher nur eine Referenz für die Entstehung von Leben kennen.Is schon ein bisserl mehr als das. Für Komplexität von Leben braucht es eine Vielzahl komplexer Molekülverbindungen und eine gute Reaktionszeit. Das Element nach Kohlenstoff, das ähnlich reaktionsfreudig ist, also eine Vielzahl von Molekülen bilden kann, ist Silizium, aber das hinkt um ca. eine Größenordnung hinterdrein. Und die Moleküle sind recht starr und reagieren langsam. Daß auf unserem Planeten ein Vielfaches an Silizium im Vergleich zu Kohlenstoff vorkommt, das Leben dennoch kohlenstoffbasiert entstanden ist, ist da auch nicht von der Hand zu weisen. Naja, und nach Silizium kommt dann auch erst mal ne Weile nichts. Insofern scheint Kohlenstoff die erste Wahl zu sein, und womöglich sogar die einzige.
JoschiX schrieb:Es ist ja nicht so als hätte sich da nie jemand mal ernsthaft Gedanken drum gedachtImmer wieder alte Denkweisen... vielleicht sind wir längst nich clever genug sowas zu verstehn oder gar nur zu erfassen, wieso kommt keiner auf diese Idee?
efficiencer schrieb:Sagen wir einfach, für kohlenstoffbasierende Lebensformen sind das wichtige Voraussetzungen, da werden wir uns sicher einig (wobei auch das nich wirklich bewiesen ist ^^)Ja, schon.
efficiencer schrieb:vielleicht sind wir längst nich clever genug sowas zu verstehn oder gar nur zu erfassen, wieso kommt keiner auf diese Idee?Ja aber diese Ideen gab und gibt es doch, sie werden sogar diskutiert in der Wissenschaft. Aber letztendlich entpuppt sich das als nicht haltbar. Siehe @perttivalkonen Einwurf mit auf siliziumbasiertes Leben.
efficiencer schrieb:das "Voraussetzungen für Leben" fix definiert wurde mit Wasser, Atmosphäre etc.Und genau diese Voraussetzungen kennen wir. Wir haben in unserem Sonnensystem doch auch Planeten und Monde mit vollkommen anderen Gegebenheiten und konnten dort, bis jetzt, keine Anzeichen für Leben entdecken.
efficiencer schrieb:Und nochmal, mir gehts nicht um Sinn oder Unsinn, sondern das man nicht mit Scheuklappen nach Leben suchen sollte, sondern mehr in Betracht ziehn als man schon kennt.Und genau das passiert doch gar nicht !
Jump up ^ David J. Des Marais; et al. (2008). "The NASA Astrobiology Roadmap" (PDF). Astrobiology 8 (4): 718. doi:10.1089/2008.0819.Das ist alles Literatur zu hypothetischem, organischem Leben.
2.Jump up ^ Davila, Alfonso F.; McKay, Christopher P. (May 27, 2014). "Chance and Necessity in Biochemistry: Implications for the Search for Extraterrestrial Biomarkers in Earth-like Environments". Astrobiology 14 (6): 534–540. Bibcode:2014AsBio..14..534D. doi:10.1089/ast.2014.1150. Retrieved 2015-03-29.
3.Jump up ^ Singer, Emily (July 19, 2015). "Chemists Invent New Letters for Nature’s Genetic Alphabet". Wired (magazine). Retrieved July 20, 2015.
4.Jump up ^ Davies, P. C. W.; Benner, S.A.; Cleland, C.E.; Lineweaver, C.H.; McKay, C.P.; Wolfe-Simon, F. (2009). "Signatures of a Shadow Biosphere". Astrobiology 9 (2): 241–249. Bibcode:2009AsBio...9..241D. doi:10.1089/ast.2008.0251. PMID 19292603.
5.Jump up ^ Cleland, Carol E.; Copley, Shelley D. (16 January 2006). "The possibility of alternative microbial life on Earth". International Journal of Astrobiology 4 (3-4): 165. doi:10.1017/S147355040500279X. archived at [1] (2009-03-20) from original [2]
6.Jump up ^ P.C.W. Davies and Charles H. Lineweaver (2005). "Hypothesis Paper: Finding a Second Sample of Life on Earth" (PDF). Astrobiology 5 (2): 159. Bibcode:2005AsBio...5..154D. doi:10.1089/ast.2005.5.154.
7.Jump up ^ Sagan, Carl; Agel, Jerome (2000). Carl Sagan's Cosmic Connection: an Extraterrestrial Perspective (2nd ed.). Cambridge U.P. p. 41. ISBN 9780521783033.
8.^ Jump up to: a b Sagan, Carl (2000). Carl Sagan's Cosmic Connection: an Extraterrestrial Perspective (2nd ed.). Cambridge U.P. p. 46.
9.Jump up ^ Sagan, Carl (2000). Carl Sagan's Cosmic Connection: an Extraterrestrial Perspective (2nd ed.). Cambridge U.P. p. 47.
10.^ Jump up to: a b c Pace, NR (2001). "The universal nature of biochemistry" (PDF). Proceedings of the National Academy of Sciences of the United States of America 98 (3): 805–8. Bibcode:2001PNAS...98..805P. doi:10.1073/pnas.98.3.805. PMC: 33372. PMID 11158550.
11.Jump up ^ Gillette, Stephen. World-Building. Writer's Digest Books. ISBN 0-89879-707-1.
12.Jump up ^ Lazio, Joseph. "F.10 Why do we assume that other beings must be based on carbon? Why couldn't organisms be based on other substances?". [sci.astro] ET Life (Astronomy Frequently Asked Questions). Retrieved 2006-07-21.
13.Jump up ^ "Astrobiology". Biology Cabinet. September 26, 2006. Retrieved 2011-01-17.
14.Jump up ^ Cairns-Smith, A. Graham (1985). Seven Clues to the Origin of Life. Cambridge: Cambridge University Press. ISBN 0-521-27522-9.
15.Jump up ^ Dawkins, Richard (1996) [1986]. The Blind Watchmaker. New York: W. W. Norton & Company, Inc. pp. 148–161. ISBN 0-393-31570-3.
16.Jump up ^ William Bains. "Astrobiology—the nature of life". WilliamBains.co.uk. Retrieved 2015-03-20.
17.Jump up ^ William Bains (June 2004). "Many Chemistries Could Be Used to Build Living Systems". Astrobiology 4 (2): 137–167. doi:10.1089/153110704323175124. PMID 15253836.
18.^ Jump up to: a b "Life-like cells are made of metal". New Scientist. September 14, 2011. Retrieved 2014-05-25.
19.Jump up ^ Early Archaean Microorganisms Preferred Elemental Sulfur, Not Sulfate Science AAAS, by Philippot, et al., (14 September 2007)
20.Jump up ^ "Biochemical Periodic Table – Arsenic". UMBBD. 2007-06-08. Retrieved 2010-05-29.
21.Jump up ^ Niggemyer, A; Spring S; Stackebrandt E; Rosenzweig RF (December 2001). "Isolation and characterization of a novel As(V)-reducing bacterium: implications for arsenic mobilization and the genus Desulfitobacterium". Appl Environ Microbiol 67 (12): 5568–80. doi:10.1128/AEM.67.12.5568-5580.2001. PMC: 93345. PMID 11722908.
22.Jump up ^ Reilly, Michael (26 April 2008). "Early life could have relied on 'arsenic DNA'". New Scientist 198 (2653): 10. doi:10.1016/S0262-4079(08)61007-6.
23.Jump up ^ Westheimer, F. H. (1987-03-06). "Why nature chose phosphates" (PDF). Science 235 (4793): 1173–1178 (see pp. 1175–1176). Bibcode:1987Sci...235.1173W. doi:10.1126/science.2434996. Retrieved 2010-12-03.
24.Jump up ^ "NASA-Funded Research Discovers Life Built With Toxic Chemical". NASA.gov. 2 December 2010. Retrieved 2010-12-02.
25.^ Jump up to: a b Wolfe-Simon, Felisa; Blum, Jodi Switzer; Kulp, Thomas R.; Gordon, Shelley E.; Hoeft, S. E.; Pett-Ridge, Jennifer; Stolz, John F.; Webb, Samuel M.; Weber, Peter K.; Davies, Paul C. W.; Anbar, Ariel D.; Oremland, Ronald S. (2 December 2010). "A Bacterium That Can Grow by Using Arsenic Instead of Phosphorus" (PDF). Science 332 (6034): 1163–6. Bibcode:2011Sci...332.1163W. doi:10.1126/science.1197258. PMID 21127214. Retrieved 2010-12-09.
26.Jump up ^ Redfield, Rosemary (4 December 2010). "Arsenic-associated bacteria (NASA's claims)". RR Research blog. Retrieved 4 December 2010. External link in |work= (help)
27.Jump up ^ Bradley, Alex (5 December 2010). "Arsenate-based DNA: a big idea with big holes". We, Beasties blog. Retrieved 9 December 2010. External link in |work= (help)
28.Jump up ^ Zimmer, Carl (7 December 2010). "Scientists see fatal flaws in the NASA study of arsenic-based life". Slate. Retrieved 7 December 2010.
29.Jump up ^ Williams, Sarah (7 November 2012). ""Arsenic Life" Claim Refuted". BioTechniques. Retrieved 23 January 2013.
30.Jump up ^ Benner, Steven A.; Ricardo, Alonso; Carrigan, Matthew A (2004). "Is there a common chemical model for life in the universe?". Current Opinion in Chemical Biology 8 (6): 676–680. doi:10.1016/j.cbpa.2004.10.003. PMID 15556414.Text as pdf from www.sciencedirect.com (accessed 13 July 2011)
31.Jump up ^ Committee on the Limits of Organic Life in Planetary Systems, Committee on the Origins and Evolution of Life, National Research Council; The Limits of Organic Life in Planetary Systems; The National Academies Press, 2007; pages 69–79
32.^ Jump up to: a b c d e Committee on the Limits of Organic Life in Planetary Systems, Committee on the Origins and Evolution of Life, National Research Council; The Limits of Organic Life in Planetary Systems; The National Academies Press, 2007; p 72
33.^ Jump up to: a b c Committee on the Limits of Organic Life in Planetary Systems, Committee on the Origins and Evolution of Life, National Research Council; The Limits of Organic Life in Planetary Systems; The National Academies Press, 2007; p 73
34.^ Jump up to: a b c Committee on the Limits of Organic Life in Planetary Systems, Committee on the Origins and Evolution of Life, National Research Council; The Limits of Organic Life in Planetary Systems; The National Academies Press, 2007; p 74
35.^ Jump up to: a b c Committee on the Limits of Organic Life in Planetary Systems, Committee on the Origins and Evolution of Life, National Research Council; The Limits of Organic Life in Planetary Systems; The National Academies Press, 2007; p 75
36.Jump up ^ Sagan, Carl (2002). Cosmos. Random House. pp. 126–127. ISBN 0-375-50832-5.
37.^ Jump up to: a b c Sagan, Carl; Head, Tom (2006). Conversations with Carl Sagan. University Press of Mississippi. p. 10. ISBN 1-57806-736-7.
38.^ Jump up to: a b c d Sagan, Carl (2002). Cosmos. Random House. p. 128. ISBN 0-375-50832-5.
39.^ Jump up to: a b c d Committee on the Limits of Organic Life in Planetary Systems, Committee on the Origins and Evolution of Life, National Research Council; The Limits of Organic Life in Planetary Systems; The National Academies Press, 2007; page 70
40.^ Jump up to: a b c d e f Isaac Asimov (Winter 1981). "Not as We Know it – the Chemistry of Life". Cosmic Search (North American AstroPhysical Observatory) (9 (Vol 3 No 1)).
41.^ Jump up to: a b J.B.S. Haldane (1954). "The Origins of Life". New Biology 16: 12–27. cited in Darling, David. "ammonia-based life". Retrieved 2012-10-01.
42.^ Jump up to: a b c Darling, David. "ammonia-based life". Retrieved 2012-10-01.
43.Jump up ^ Feinberg, Gerald; Robert Shapiro (1980). Life Beyond Earth. Morrow. ISBN 9780688036423. cited in Darling, David. "ammonia-based life". Retrieved 2012-10-01.
44.^ Jump up to: a b Schulze-Makuch, Dirk; Irwin, Louis Neal (2008). Life in the Universe: Expectations and Constraints (2 ed.). Springer. p. 119. ISBN 9783540768166.
45.Jump up ^ Fortes, A. D. (1999). "Exobiological Implications of a Possible Ammonia-Water Ocean Inside Titan". Retrieved 7 June 2010.
46.^ Jump up to: a b c d e Committee on the Limits of Organic Life in Planetary Systems, Committee on the Origins and Evolution of Life, National Research Council; The Limits of Organic Life in Planetary Systems; The National Academies Press, 2007; page 74.
47.Jump up ^ McLendon, Christopher; Opalko, F. Jeffrey (March 2015). "Solubility of Polyethers in Hydrocarbons at Low Temperatures. A Model for Potential Genetic Backbones on Warm Titans". Astrobiology 15 (3): 200–206. Bibcode:2015AsBio..15..200M. doi:10.1089/ast.2014.1212. Retrieved 2015-03-25.
48.Jump up ^ Hadhazy, Adam (13 May 2015). "Alien Life on Oily Exoplanets Could Have Ether-based 'DNA'". Astrobiology Magazine (Space.com). Retrieved 2015-05-21.
49.^ Jump up to: a b c "What is Consuming Hydrogen and Acetylene on Titan?". NASA/JPL. 2010. Retrieved 2010-06-06.
50.^ Jump up to: a b McKay, C. P.; Smith, H. D. (2005). "Possibilities for methanogenic life in liquid methane on the surface of Titan". Icarus 178 (1): 274–276. Bibcode:2005Icar..178..274M. doi:10.1016/j.icarus.2005.05.018.
51.Jump up ^ Strobel, Darrell F. (2010). "Molecular hydrogen in Titan's atmosphere: Implications of the measured tropospheric and thermospheric mole fractions" (PDF). Icarus 208 (2): 878–886. Bibcode:2010Icar..208..878S. doi:10.1016/j.icarus.2010.03.003.
52.^ Jump up to: a b Mckay, Chris (2010). "Have We Discovered Evidence For Life On Titan". New Mexico State University, College of Arts and Sciences, Department of Astronomy. Retrieved 2014-05-15. External link in |publisher= (help)
53.Jump up ^ Life 'not as we know it' possible on Saturn's moon Titan
54.^ Jump up to: a b Sneath, P.H.A. (1970). Planets and Life. Thames and Hudson. cited in Boyce, Chris (1981). Extraterrestrial Encounter. New English Library. pp. 125, 182.
55.Jump up ^ Jander, Gerhart; Spandau, Hans; Addison, C.C. (1971). Chemistry in Nonaqueous Ionizing solvents: Inorganic Chemistry in Liquid Hydrogen Cyanide and Liquid hydrogen Fluoride II. N.Y.: Pergamon Press. cited in Freitas, Robert A. (1979). "8.2.2". Xenology: An Introduction to the Scientific Study of Extraterrestrial Life, Intelligence, and Civilization. Sacramento, CA: Xenology Research Institute.
56.Jump up ^ Freitas, Robert A. (1979). "8.2.2". Xenology: An Introduction to the Scientific Study of Extraterrestrial Life, Intelligence, and Civilization. Sacramento, CA: Xenology Research Institute.
57.Jump up ^ Darling, David. "solvent". Retrieved 2012-10-12.
58.Jump up ^ Jander, J.; Lafrenz, C. (1970). Ionizing Solvents I. Weinheim/Bergstr.: John Wiley & Sons Ltd., Verlag Chemie. cited in Freitas, Robert A. (1979). "8.2.2". Xenology: An Introduction to the Scientific Study of Extraterrestrial Life, Intelligence, and Civilization. Sacramento, CA: Xenology Research Institute.
59.Jump up ^ Choi, Charles Q. "The Chance for Life on Io". Retrieved 2013-05-25.
60.Jump up ^ David W. Koerner and Simon LeVay (2000). Here Be Dragons : The Scientific Quest for Extraterrestrial Life:. Oxford U.P. p. 202. ISBN 9780198033370.
61.^ Jump up to: a b Budisa, Nediljko; Schulze-Makuch, Dirk (8 August 2014). "Supercritical Carbon Dioxide and Its Potential as a Life-Sustaining Solvent in a Planetary Environment". Life 4 (3): 331–340. doi:10.3390/life4030331.
62.^ Jump up to: a b Ward, Peter D.; Benner, Steven A. (2007). "Alien biochemistries". In Sullivan, Woodruff T.; Baross, John A. Planets and Life. Cambridge: Cambridge. p. 540. ISBN 978-0521531023.
63.Jump up ^ The methane habitable zone
64.Jump up ^ Houtkooper, Joop M.; Dirk Schulze-Makuch (2007-05-22). "A Possible Biogenic Origin for Hydrogen Peroxide on Mars". International Journal of Astrobiology 6 (2): 147. arXiv:physics/0610093. Bibcode:2007IJAsB...6..147H. doi:10.1017/S1473550407003746.
65.Jump up ^ Houtkooper, Joop M.; Dirk Schulze-Makuch (2007). "The H2O2-H2O Hypothesis: Extremophiles Adapted to Conditions on Mars?" (PDF). EPSC Abstracts (European Planetary Science Congress 2007) 2: 558. Bibcode:2007epsc.conf..558H. EPSC2007-A-00439.
66.Jump up ^ Ellison, Doug (2007-08-24). "Europlanet : Life's a bleach". Planetary.org.
67.Jump up ^ "NASA – NASA Predicts Non-Green Plants on Other Planets". Nasa.gov. 2008-02-23. Retrieved 2010-05-29.
68.^ Jump up to: a b Kiang, Nancy Y.; Segura, Antígona; Tinetti, Giovanna; Jee, Govind; Blankenship, Robert E.; Cohen, Martin; Siefert, Janet; Crisp, David; Meadows, Victoria S. (2007-04-03). "Spectral signatures of photosynthesis. II. Coevolution with other stars and the atmosphere on extrasolar worlds". Astrobiology (Mary Ann Liebert, Inc.) 7 (1): 252–274. arXiv:astro-ph/0701391. Bibcode:2007AsBio...7..252K. doi:10.1089/ast.2006.0108. PMID 17407410. Retrieved 2010-12-03.
69.^ Jump up to: a b "Christmas in Yellowstone". Pbs.org. Retrieved 2010-05-29.
70.Jump up ^ Main and Bentley, Ecology, "Water Relations of Australian Burrowing Frogs and Tree Frogs" (1964)
71.Jump up ^ "Physicists Discover Inorganic Dust With Lifelike Qualities". Science Daily. 2007-08-15.
72.Jump up ^ Tsytovich, V N; G E Morfill, V E Fortov, N G Gusein-Zade, B A Klumov and S V Vladimirov; Fortov, V E; Gusein-Zade, N G; Klumov, B A; Vladimirov, S V (14 August 2007). "From plasma crystals and helical structures towards inorganic living matter". New J. Phys. 9 (263): 263. Bibcode:2007NJPh....9..263T. doi:10.1088/1367-2630/9/8/263.
73.Jump up ^ W. Bains (2004). "Many Chemistries Could Be Used to Build Living Systems". Astrobiology 4 (2): 137–167. Bibcode:2004AsBio...4..137B. doi:10.1089/153110704323175124. PMID 15253836.
74.Jump up ^ Committee on the Limits of Organic Life in Planetary Systems, Committee on the Origins and Evolution of Life, National Research Council; The Limits of Organic Life in Planetary Systems; The National Academies Press, 2007.
75.Jump up ^ Committee on the Limits of Organic Life in Planetary Systems, Committee on the Origins and Evolution of Life, National Research Council; The Limits of Organic Life in Planetary Systems; The National Academies Press, 2007; page 5
76.Jump up ^ Feinberg, Gerald; Robert Shapiro (1980). Life Beyond Earth. Morrow. ISBN 0688036422.
77.Jump up ^ A detailed review of this book is: John Gribbin (2 Oct 1980). "Life beyond Earth". New Scientist: xvii.
78.Jump up ^ V. Axel Firsoff (January 1962). "An Ammonia-Based Life". Discovery 23: 36–42. cited in Darling, David. "ammonia-based life". Retrieved 2012-10-01.
79.Jump up ^ Freitas, Robert A. (1979). Xenology: An Introduction to the Scientific Study of Extraterrestrial Life, Intelligence, and Civilization. Sacramento, CA: Xenology Research Institute.
80.Jump up ^ This work is acknowledged the partial basis of the article Darling, David. "ammonia-based life". Retrieved 2012-10-01.
81.^ Jump up to: a b Shklovskii, I.S.; Carl Sagan (1977). Intelligent Life in the Universe. Picador. p. 229.