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Bernoulli, Darwin, and Sagan: the probability of life on other planets

  • D. Kim Rossmo (a1)
Abstract

The recent discovery that billions of planets in the Milky Way Galaxy may be in circumstellar habitable zones has renewed speculation over the possibility of extraterrestrial life. The Drake equation is a probabilistic framework for estimating the number of technological advanced civilizations in our Galaxy; however, many of the equation's component probabilities are either unknown or have large error intervals. In this paper, a different method of examining this question is explored, one that replaces the various Drake factors with the single estimate for the probability of life existing on Earth. This relationship can be described by the binomial distribution if the presence of life on a given number of planets is equated to successes in a Bernoulli trial. The question of exoplanet life may then be reformulated as follows – given the probability of one or more independent successes for a given number of trials, what is the probability of two or more successes? Some of the implications of this approach for finding life on exoplanets are discussed.

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Corresponding author
e-mail: krossmo@txstate.edu
References
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Ambassador for Earth: Is it time for SETI to reach out to the stars? (2006). Nature 443, 606.
Bonfils, X. et al. (2011). The HARPS search for southern extra-solar planets XXXI. The M-dwarf sample. Astron. Astrophys. 526, A112.
Carter, B. (2011). Large number coincidences and the anthropic principle in cosmology. Gen. Relat. Gravit. 43, 32253233.
Cassan, A. et al. (2012). One or more bound planets per Milky Way star from microlensing observations. Nature 481, 167169.
Crawford, I.A. (2000). Where are they? Maybe we are alone in the galaxy after all. Sci. Am. 283(1), 3843.
Darwin, C. (1859). On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life. John Murray, London.
Dennett, D.C. (1995). Darwin's Dangerous Idea: Evolution and the Meanings of Life. Simon & Schuster, New York.
Diamond, J.M. (2005). Collapse: How Societies Choose to Fail or Succeed. Viking, New York.
Doomsday Clock (2012). Bulletin of the Atomic Scientists. http://www.thebulletin.org/content/doomsday-clock/timeline.
Eddy, S.R. (2004). What is Bayesian statistics? Nature Biotechnology 22, 11771178.
Evans, M., Hastings, N. & Peacock, B. (2000). Statistical Distributions. 3rd edn. John Wiley & Sons, New York.
Gould, S.J. (1996). Full House: The Spread of Excellence from Plato to Darwin. Harmony Books, New York.
Jenkins, J.M. et al. (2015). Discovery and validation of Kepler-452b: a 1.6-R super Earth exoplanet in the habitable zone of a G2 star. Astron. J. 150, 56.
Overbye, D. (2015). Astronomers have found an analogue for the Earth. The New York Times 24 July, p. A20.
Sagan, C. (1980). Cosmos. Random House, New York.
Sterelny, K. & Griffiths, P.E. (1999). Sex and Death: An Introduction to Philosophy of Biology. University of Chicago Press, Chicago.
The Drake equation (2015). SETI Institute. http://www.seti.org/drakeequation.
Ward, P.D. & Brownlee, D. (2000). Rare Earth: Why Complex Life is Uncommon in the Universe. Copernicus Books, New York.
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International Journal of Astrobiology
  • ISSN: 1473-5504
  • EISSN: 1475-3006
  • URL: /core/journals/international-journal-of-astrobiology
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