Skip to main content
×
×
Home

The Galactic Club or Galactic Cliques? Exploring the limits of interstellar hegemony and the Zoo Hypothesis

  • Duncan H. Forgan (a1)
Abstract
Abstract

The Zoo solution to Fermi's Paradox proposes that extraterrestrial intelligences (ETIs) have agreed to not contact the Earth. The strength of this solution depends on the ability for ETIs to come to agreement, and establish/police treaties as part of a so-called ‘Galactic Club’. These activities are principally limited by the causal connectivity of a civilization to its neighbours at its inception, i.e. whether it comes to prominence being aware of other ETIs and any treaties or agreements in place. If even one civilization is not causally connected to the other members of a treaty, then they are free to operate beyond it and contact the Earth if wished, which makes the Zoo solution ‘soft’. We should therefore consider how likely this scenario is, as this will give us a sense of the Zoo solution's softness, or general validity. We implement a simple toy model of ETIs arising in a Galactic Habitable Zone, and calculate the properties of the groups of culturally connected civilizations established therein. We show that for most choices of civilization parameters, the number of culturally connected groups is >1, meaning that the Galaxy is composed of multiple Galactic Cliques rather than a single Galactic Club. We find in our models for a single Galactic Club to establish interstellar hegemony, the number of civilizations must be relatively large, the mean civilization lifetime must be several millions of years, and the inter-arrival time between civilizations must be a few million years or less.

Copyright
Corresponding author
e-mail: dhf3@st-andrews.ac.uk
References
Hide All
Annis J. (1999). J. Br. Interplanet. Soc. 52, 19.
Ball J. (1973). Icarus 19, 347.
Brin G.D. (1983). Q. J. R. Astron. Soc. 24, 283.
Carter B. (2008). Int. J. Astrobiol. 7, 177.
Cirkovic M.M. (2009). Serbian Astron. J. 178, 1.
Fogg M. (1987). Icarus 69, 370.
Forgan D., Dayal P., Cockell C. & Libeskind N. (2015). Int. J. Astrobiol., in press, arXiv:1511.01786, available online, DOI:10.1017/S1473550415000518
Forgan D.H. (2009). Int. J. Astrobiol. 8, 121.
Forgan D.H. (2011). Int. J. Astrobiol. 10, 341.
Forgan D.H. & Rice K. (2010). Int. J. Astrobiol. 9, 73.
Freitas R.A. (1977). Mercury 6, 15.
Gowanlock M.G., Patton D.R. & McConnell S.M. (2011). Astrobiology 11, 855.
Hair T.W. (2011). Int. J. Astrobiol. 10, 131.
Hart M.H. (1975). Q. J. R. Astron. Soc. 16, 128.
Lineweaver C.H., Fenner Y. & Gibson B.K. (2004). Science 303, 59.
Martin O., Cardenas R., Guimarais M., Peñate L., Horvath J. & Galante D. (2010). Astrophys. Space Sci. 326, 61.
McDougall I., Brown F.H. & Fleagle J.G. (2005). Nature 433, 733.
O'Malley-James J.T., Greaves J.S., Raven J.A. & Cockell C.S. (2013). Int. J. Astrobiol. 12, 99.
Raup D.M. & Sepkoski J.J. (1982). Science 215, 1501.
Rocha-Pinto H.J., Maciel W.J., Scalo J. & Flynn C. (2000). Astron. Astrophys. 358, 850, 869.
Rushby A.J., Claire M.W., Osborn H. & Watson A.J. (2013). Astrobiology 13, 833.
Snyder D.L. & Miller M.I. (1991). Random Point Processes in Time and Space. Springer-Verlag, New York.
Stevens A., Forgan D. & O'Malley-James J. (2015). Int. J. Astrobiol. 15, 333.
Thomas B. (2009). Int. J. Astrobiol. 8, 183.
Vukotic B. & Cirkovic M.M. (2007). Serb. Astron. J. 175, 45.
Vukotić B., Steinhauser D., Martinez-Aviles G., Ćirković M.M., Micic M. & Schindler S. (2016). Mon. Not. R. Astron. Soc. 459, 3512.
Wright J.T., Cartier K.M.S., Zhao M., Jontof-Hutter D. & Ford E.B. (2015). Astrophys. J. 816, 17.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

International Journal of Astrobiology
  • ISSN: 1473-5504
  • EISSN: 1475-3006
  • URL: /core/journals/international-journal-of-astrobiology
Please enter your name
Please enter a valid email address
Who would you like to send this to? *
×

Keywords:

Metrics

Altmetric attention score

Full text views

Total number of HTML views: 12
Total number of PDF views: 73 *
Loading metrics...

Abstract views

Total abstract views: 532 *
Loading metrics...

* Views captured on Cambridge Core between 28th November 2016 - 21st February 2018. This data will be updated every 24 hours.