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Fermi's paradox, extraterrestrial life and the future of humanity: a Bayesian analysis

Published online by Cambridge University Press:  11 January 2016

Vilhelm Verendel*
Affiliation:
Department of Energy and Environment, Chalmers University of Technology, 412 96, Gothenburg, Sweden
Olle Häggström
Affiliation:
Department of Mathematical Sciences, Chalmers University of Technology, 412 96, Gothenburg, Sweden

Abstract

The Great Filter interpretation of Fermi's great silence asserts that Npq is not a very large number, where N is the number of potentially life-supporting planets in the observable universe, p is the probability that a randomly chosen such planet develops intelligent life to the level of present-day human civilization, and q is the conditional probability that it then goes on to develop a technological supercivilization visible all over the observable universe. Evidence suggests that N is huge, which implies that pq is very small. Hanson (1998) and Bostrom (2008) have argued that the discovery of extraterrestrial life would point towards p not being small and therefore a very small q, which can be seen as bad news for humanity's prospects of colonizing the universe. Here we investigate whether a Bayesian analysis supports their argument, and the answer turns out to depend critically on the choice of prior distribution.

Type
Research Article
Copyright
Copyright © Cambridge University Press 2016 

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References

Aldous, D.J. (2012). The great filter, branching histories and unlikely events. Math. Sci. 37(1), 5564.Google Scholar
Armstrong, S. (2011). Anthropic decision theory. arXiv:1110.6437.Google Scholar
Armstrong, S. & Sandberg, A. (2013). Eternity in six hours: intergalactic spreading of intelligent life and sharpening the Fermi paradox. Acta Astronaut. 89, 113.CrossRefGoogle Scholar
Bostrom, N. (2002). Anthropic Bias: Observation Selection Effects in Science and Philosophy. Routledge, New York.Google Scholar
Bostrom, N. (2008). Where are they? Why I hope the search for extraterrestrial life finds nothing. MIT Technology Review May/June, 7277.Google Scholar
Bostrom, N. (2014). Superintelligence: Paths, Dangers, Strategies. Oxford University Press, Oxford.Google Scholar
Bostrom, N. & Cirkovic, M.M. (2008). Global Catastrophic Risks. Oxford University Press, Oxford.CrossRefGoogle Scholar
Brandt, T.D. & Spiegel, D.S. (2014). Prospects for detecting oxygen, water, and chlorophyll on an exo-earth. Proc. Natl. Acad. Sci. 111(37), 1327813283.Google Scholar
Cassan, A. et al. (2012). One or more bound planets per Milky Way star from microlensing observations. Nature 481(7380), 167169.Google Scholar
Ćirković, M. (2009). Fermi's paradox: the last challenge for copernicanism? Serb. Astron. J. 178, 120.Google Scholar
Cox, D. & Hinkley, D. (1979). Theoretical Statistics. Chapman and Hall, London.CrossRefGoogle Scholar
Griffith, R.L., Wright, J.T., Maldonado, J., Povich, M.S., Sigurdsson, S. & Mullan, B. (2015). The ĝ infrared search for extraterrestrial civilizations with large energy supplies. iii. The reddest extended sources in wise. Astrophys. J. Suppl. Ser. 217(2), 25.CrossRefGoogle Scholar
Häggström, O. (2007). Uniform distribution is a model assumption. http://www.math.chalmers.se/~olleh/reply_to_Dembski.pdf.Google Scholar
Häggström, O. (2016). Here Be Dragons: Science, Technology and the Future of Humanity. Oxford University Press, Oxford. To appear.Google Scholar
Hanson, R. (1998). The great filter – are we almost past it? http://hanson.gmu.edu/greatfilter.html.Google Scholar
Hart, M. (1975). Explanation for the absence of extraterrestrials on earth. Q. J. R. Astron. Soc. 16, 128135.Google Scholar
Martin, J. (2006). The Meaning of the 21st Century: A vital Blueprint for Ensuring our Future. Transworld, London.Google Scholar
Pamlin, D. & Armstrong, S. (2015). Global Challenges: 12 Risks that Threaten Human Civilization. Global Challenges Foundation, Stockholm.Google Scholar
Petigura, E.A., Howard, A.W. & Marcy, G.W. (2013). Prevalence of Earth-size planets orbiting sun-like stars. Proc. Natl. Acad. Sci. 110(48), 1927319278.Google Scholar
Quintana, E.V. et al. (2014). An Earth-sized planet in the habitable zone of a cool star. Science 344(6181), 277280.Google Scholar
Rees, M. (2003). Our Final Century: Will the Human Race Survive the Twenty-first Century? William Heinemann, London.Google Scholar
Salsburg, D. (2001). The lady tasting tea: How statistics revolutionized science in the twentieth century.Google Scholar
Tegmark, M. (2014). Our Mathematical Universe: My Quest for the Ultimate Nature of Reality. Allen Lane, London.Google Scholar
Webb, S. (2002). If the Universe is Teeming with Aliens… Where is Everybody?: Fifty Solutions to the Fermi Paradox and the Problem of Extraterrestrial Life. Copernicus Books, New York.Google Scholar
Wolfram, S. (2002). A New Kind of Science. Wolfram media, Champaigne, IL.Google Scholar