Monte Carlo probabilities of causal contacts between galactic intelligences using discrete event simulations

LARES, MARCELO; FUNES, JOSÉ G.; GRAMAJO, LUCIANA

Congreso; Reunión Anual de la AAA; 2020

Asociación Argentina de Astronomía

The number of intelligent civilizations in the Galaxy is one of the most important unansweredquestions in modern science. A related (but different) problem is to assess the chance of contacts among locationswith communication capability, assuming they exist. Here we present a model for a communication network thatallows to estimate the probabilities of causal contacts constrained to a maximum separation between the nodesin the network. The model has three parameters, which we argue comprise the minimum number of assumptionsabout the statistical properties of the distribution of intelligence in the Galaxy, considering the time variableas a key factor. We make no assumptions about the origin of life or any other factor in the Drake equation,except for the mean lifetime of a node. The model also considers the maximum distance a signal can be detectedand the density of active nodes in time, and assumes statistical patterns that are observed in a plethora ofphenomena in nature. We analyze many numerical Monte Carlo simulations of the model through a discreteevents implementation. The simulation suite allows to estimate probabilities of contacts, the distributions of thewaiting times for the first contact and the distributions of the number of contacts as a function of the modelparameters, among other quantities. We find that a node has a low probability, for an observing time of somedecades, to make contacts to other nodes in the network, except for models that resemble a densely populatedGalaxy with long-standing civilizations. The probability of causal contacts also increases with the lifetime ofthe nodes more significantly than with their number, reaching a maximum at the discovery of the requiredcommunication technology.