[LINK] "Homogeneous cosmology with aggressively expanding civilizations"

[rfmcdonald]

The Dragon's Tale linked to S. Jay Olson's recent <a href="http://arxiv.org/abs/1411.4359arXiV paper. Its abstract describes the paper's rather provocative explorations.

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 covering 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.

After exploring various models for the spread of civilization across intergalactic distances, and noting the likely effects in terms of radiation consumption, the paper makes some provocative analogies and suggestions.

We have argued that the dynamics of nucleation and bubble growth in a first-order phase transition is naturally carried over to a description of aggressively expanding life saturating the universe, due to the geometrical similarities (spatially random events and spherical expansion). However, due to the abundance of waste radiation appearing in this picture, it is tempting to regard the effects of aggressively expanding life as a literal thermodynamic phase transformation -- an abrupt change to the equation of state and thermodynamic variables describing the universe. We are accustomed to regarding the thermal effects of life as due to very special initial conditions. A Petri dish, for example, filled with nutrients and a few bacteria can be expected to have a very different thermodynamic future than a Petri dish filled with nutrients alone, due to the special initial conditions implied by specifying that bacteria are present -- the initial conditions are pre-configured for an immediate collapse in the free energy. The cosmological process we have described, however, begins with no life initially, so it must represent a general kind of transition between states, i.e. one that is not merely a consequence of fine-tuning the initial conditions. The statistical process by which the universe ends and abruptly transitions to the radiation-filled, higher-entropy state we have described is not through thermal uctuations or tunneling directly to a new vacuum -- it is through the elaborate and indirect route of evolving life and general intelligence that forever hungers for new sources of free energy.