The Edges of Our Universe

TL;DR

This paper investigates the fundamental causal boundaries of the universe, defining regions based on observability and influence, and discusses their implications for the long-term capabilities of spacefaring civilizations.

Contribution

It introduces a framework categorizing causal limits in the universe and analyzes their impact on the potential achievements of future spacefaring civilizations.

Findings

Defines four principal causal regions of the universe.

Establishes physical bounds on long-term spacefaring capabilities.

Highlights implications for future technological and observational limits.

Abstract

This paper explores the fundamental causal limits on how much of the universe we can observe or affect. It distinguishes four principal regions: the affectable universe, the observable universe, the eventually observable universe, and the ultimately observable universe. It then shows how these (and other) causal limits set physical bounds on what spacefaring civilisations could achieve over the longterm future.