The Fermi Paradox, Self-Replicating Probes, and the Interstellar Transportation Bandwidth (1111.6131v1)

Abstract: It has been widely acknowledged that self-replicating space-probes (SRPs) could explore the galaxy very quickly relative to the age of the galaxy. An obvious implication is that SRPs produced by extraterrestrial civilizations should have arrived in our solar system millions of years ago, and furthermore, that new probes from an ever-arising supply of civilizations ought to be arriving on a constant basis. The lack of observations of such probes underlies a frequently cited variation of the Fermi Paradox. We believe that a predilection for ETI-optimistic theories has deterred consideration of incompatible theories. Notably, SRPs have virtually disappeared from the literature. In this paper, we consider the most common arguments against SRPs and find those arguments lacking. By extension, we find recent models of galactic exploration which explicitly exclude SRPs to be unfairly handicapped and unlikely to represent natural scenarios. We also consider several other models that seek to explain the Fermi Paradox, most notably percolation theory and two societal-collapse theories. In the former case, we find that it imposes unnatural assumptions which likely render it unrealistic. In the latter case, we present a new theory of interstellar transportation bandwidth which calls into question the validity of societal-collapse theories. Finally, we offer our thoughts on how to design future SETI programs which take the conclusions of this paper into account to maximize the chance of detection.

• The paper re-evaluates self-replicating probes in galactic colonization models and introduces the concept of Interstellar Transportation Bandwidth (ITB).
• It argues current models should integrate self-replicating probes (SRPs), suggesting their potential undetected presence could explain the Fermi Paradox.
• The Interstellar Transportation Bandwidth (ITB) is introduced, proposing that limited resource flow creates independent stellar societies less vulnerable to system-wide collapse.

Exploration of the Fermi Paradox through Self-Replicating Probes and Interstellar Transportation Bandwidth

The paper "The Fermi Paradox, Self-Replicating Probes, and the Interstellar Transportation Bandwidth" by Keith B. Wiley presents a critical examination of how self-replicating space-probes (SRPs) could provide insight into the long-standing Fermi Paradox—why we have not detected extraterrestrial intelligence (ETI) despite the apparent potential for such civilizations to colonize the galaxy. Wiley critiques traditional dismissals of SRPs and explores models of galactic exploration and societal collapse, proposing novel perspectives that may influence future SETI strategies.

Self-Replicating Probes (SRPs) and Galactic Colonization

The concept of SRPs suggests that advanced extraterrestrial civilizations could dispatch robotic probes capable of self-replication to achieve rapid galactic exploration. Wiley revisits debates surrounding SRPs, particularly opposing views from Sagan and Newman, who argue against the development of SRPs due to their inherent risks. Wiley challenges this perspective, advocating that engineered probe replication could achieve exceptional reliability, paralleling biological replication's error rates. The paper estimates that the sheer number of SRPs that could exist in our solar system presents a significant empirical test for existing theories, which have largely excluded SRPs without comprehensive justification.

Critical Review of Current Models Excluding SRPs

Wiley scrutinizes current models of galactic exploration, such as those by Bjørk and Cotta & Morales, which deliberately exclude SRPs, potentially narrowing their representational scope. By integrating SRPs and considering rapid colonization, Wiley suggests these models could more realistically reflect extraterrestrial expansion dynamics, questioning the exclusion's validity and proposing more encompassing analyses.

Percolation Theory and Galactic Boundaries

The paper extends beyond SRPs by exploring percolation theory, which suggests galactic expansion might inherently halt due to non-colonizing voids. Wiley introduces modifications to these models by incorporating elements like colony death and state mutation, demonstrating that reasonable assumptions could transform bounded expansions into potentially unbounded explorations. These insights challenge the notion that galactic colonization might naturally encounter insurmountable barriers.

Interstellar Transportation Bandwidth (ITB)

A pivotal contribution of the paper is the introduction of the Interstellar Transportation Bandwidth (ITB). Wiley postulates that the limited capacity to physically transport resources or population between solar systems shields individual stellar societies from societal collapse contagions. This notion reframes interstellar colonization as a speciation event, with distinct stellar societies evolving independently rather than as a monolithic expansion prone to systemic failure.

Implications for the Fermi Paradox and SETI Directions

The extrapolation of Wiley's theories suggests that the Fermi Paradox might not be a paradox at all if SRPs arrived undetected, aligning with Freitas' hypothesis that probes might already inhabit our solar system. The research encourages a diversified strategy for SETI, one that expands beyond traditional electromagnetic searches in our galaxy to include targeted solar system investigations and extragalactic studies. Wiley posits that other galaxies could host detectable civilizations, reinforcing the need for broader search parameters.

Conclusion

Keith B. Wiley's paper advances the discourse on the Fermi Paradox by pressing for the reintegration of SRPs into galactic colonization models and the introduction of the ITB concept to address interstellar societal dynamics. It suggests modifications to foundational tools like the Drake Equation, enhancing its applicability. These insights invite a reevaluation of our search methodologies for extraterrestrial life, broadening the scope to include underexplored observational opportunities, ultimately enriching the SETI's strategic framework.