Homogeneous cosmology with aggressively expanding civilizations

TL;DR

This paper models the spread of aggressive civilizations in a homogeneous universe using a phase transition analogy, exploring their impact on cosmic evolution and potential observability.

Contribution

It introduces a novel cosmological model for aggressive life expansion, adapting phase transition theory to include probabilistic strategies and resource consumption.

Findings

Expansion dynamics depend on strategy probabilities

Life could significantly alter universe's evolution

Observable signatures may indicate advanced civilizations

Abstract

In the context of a homogeneous universe, we note that the appearance of aggressively expanding advanced life is geometrically similar to the process of nucleation and bubble growth in a first-order cosmological phase transition. We exploit this similarity to describe the dynamics of life saturating the universe on a cosmic scale, adapting the phase transition model to incorporate probability distributions of expansion and resource consumption strategies. Through a series of numerical solutions spanning several orders of magnitude in the input assumption parameters, the resulting cosmological model is used to address basic questions related to the intergalactic spreading of life, dealing with issues such as timescales, observability, competition between strategies, and first-mover advantage. Finally, we examine physical effects on the universe itself, such as reheating and the backreaction on the evolution of the scale factor, if such life is able to control and convert a significant fraction of the available pressureless matter into radiation. We conclude that the existence of life, if certain advanced technologies are practical, could have a significant influence on the future large-scale evolution of the universe.