Cosmological horizons

TL;DR

This paper reviews cosmological horizons within the standard Lambda Cold Dark Matter model, using recent JWST data and graphical tools to aid understanding of light propagation in an expanding universe.

Contribution

It provides an accessible review of cosmological horizons with updated data and visualizations suitable for university physics education.

Findings

Graphical representations of horizons in conformal and proper coordinates

Updated understanding of light propagation in the universe's expansion

Educational tools for teaching cosmological horizons

Abstract

The recently unveiled deep-field images from the James Webb Space Telescope have renewed interest in what we can and cannot see of the universe. Answering these questions requires understanding the so-called "cosmological horizons" and the "Hubble sphere". Here we review the topic of cosmological horizons in a form that university physics teachers can use in their lessons, using the latest data about the so-called standard "Lambda Cold Dark Matter" ($\Lambda$CDM) model. Graphical representations are plotted in terms of both conformal and proper coordinates as an aid to understanding the propagation of light in the expanding universe at various epochs.