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References
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Abstract
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The abundance of intelligent civilizations in the Galaxy is a longstanding question, often conceptualized as the problem of the lack of received communication. Estimates of the number of civilizations are generally guided by the Drake equation, despite the large uncertainties in its factors and its lack of a temporal nature. Alternative approaches use detailed numerical simulations of the galaxy and recipes for the stars and planets formation rates and for the origin of life, and rely on uncertain parameters.  We present a statistical model for the abundance and duration of civilizations implemented through Monte Carlo simulations. We explore the hypothesis space of the model by a suite of simulations to analyze the emergence of communicating nodes and their causal connections. We based this on minimal assumptions and three free parameters, with focus on the proposed statistical properties of empirical models. Our analysis of the dependence of the rate of causal contacts on the mean number of civilizations, the mean lifespan distribution and the maximum distance a civilization can send signals, is considered to discuss the spatial and temporal structure of a populated galaxy within several scenarios. We find that, given the enormous distances involved, causal contacts between civilizations are very rare. The odds to make a contact in a few years of monitoring are low for most models, except for those of a galaxy densely populated with long-lived civilizations. The probability of causal contacts increases with the lifetime of civilizations much more significantly than with the number of active civilizations for a time window. We show that the maximum probability of making a contact occurs when a civilization gains the required communication technology.          

Context
================

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.. bibliography:: biblio_seti.bib
  :cited:
  :style: plain
  :encoding: latin