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

Published online by Cambridge University Press:  25 April 2016

D. Kim Rossmo
D. Kim Rossmo*
Affiliation:
Texas State University, 601 University Drive, San Marcos, Texas 78666, USA
*
e-mail: [email protected]
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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.

Keywords

astrobiologyBernoulli trialsexoplanetsextraterrestrial life probabilityprobability analysis
Type
Research Article
Information
International Journal of Astrobiology , Volume 16 , Issue 2 , April 2017 , pp. 185 - 189
Copyright
Copyright © Cambridge University Press 2016 

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References

Ambassador for Earth: Is it time for SETI to reach out to the stars? (2006). Nature 443, 606.CrossRefGoogle Scholar
Bonfils, X. et al. (2011). The HARPS search for southern extra-solar planets XXXI. The M-dwarf sample. Astron. Astrophys. 526, A112.Google Scholar
Carter, B. (2011). Large number coincidences and the anthropic principle in cosmology. Gen. Relat. Gravit. 43, 3225–3233.CrossRefGoogle Scholar
Cassan, A. et al. (2012). One or more bound planets per Milky Way star from microlensing observations. Nature 481, 167–169.Google Scholar
Crawford, I.A. (2000). Where are they? Maybe we are alone in the galaxy after all. Sci. Am. 283(1), 38–43.Google Scholar
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.Google Scholar
Dennett, D.C. (1995). Darwin's Dangerous Idea: Evolution and the Meanings of Life. Simon & Schuster, New York.Google Scholar
Diamond, J.M. (2005). Collapse: How Societies Choose to Fail or Succeed. Viking, New York.Google Scholar
Doomsday Clock (2012). Bulletin of the Atomic Scientists. http://www.thebulletin.org/content/doomsday-clock/timeline.Google Scholar
Eddy, S.R. (2004). What is Bayesian statistics? Nature Biotechnology 22, 1177–1178.Google Scholar
Evans, M., Hastings, N. & Peacock, B. (2000). Statistical Distributions. 3rd edn. John Wiley & Sons, New York.Google Scholar
Gould, S.J. (1996). Full House: The Spread of Excellence from Plato to Darwin. Harmony Books, New York.CrossRefGoogle Scholar
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.CrossRefGoogle Scholar
Overbye, D. (2015). Astronomers have found an analogue for the Earth. The New York Times 24 July, p. A20.Google Scholar
Sagan, C. (1980). Cosmos. Random House, New York.Google Scholar
Sterelny, K. & Griffiths, P.E. (1999). Sex and Death: An Introduction to Philosophy of Biology. University of Chicago Press, Chicago.Google Scholar
The Drake equation (2015). SETI Institute. http://www.seti.org/drakeequation.Google Scholar
Ward, P.D. & Brownlee, D. (2000). Rare Earth: Why Complex Life is Uncommon in the Universe. Copernicus Books, New York.Google Scholar