Interpretations of cosmic expansion: anchoring conceptions and misconceptions

TL;DR

This paper examines two common interpretations of cosmic expansion taught at the undergraduate and high school levels, analyzing their potential to foster correct understanding or misconceptions among students.

Contribution

It compares the popular space-expanding interpretation with the relativistic explosion view, highlighting pedagogical implications and student preconceptions.

Findings

The space-expanding interpretation can lead to misconceptions about galaxies being stationary.

The relativistic explosion interpretation offers an alternative view that may reduce misconceptions.

Understanding student preconceptions is crucial for effective cosmology teaching.

Abstract

Teaching cosmology at the undergraduate or high school level requires simplifications and analogies, and inevitably brings the teacher into contact with at least one of the pedagogical interpretations of the expanding universe. The by far most popular interpretation holds that galaxies in an expanding universe are stationary, while space itself expands and thus causes the growing distances that characterize cosmic expansion. The alternative relativistic explosion interpretation regards cosmic expansion as a pattern of (relativistic) galaxy motion. The aim of this article is to discuss the two competing interpretations from the perspective of potential student preconceptions, taking into account both beneficial anchoring conceptions and potentially harmful preconceptions that can lead to misconceptions.