The Challenging History of Other Earths

TL;DR

This paper reviews the historical scientific debates on the idea of multiple inhabited worlds orbiting stars, highlighting past challenges and the persistence of pluralism despite scientific objections.

Contribution

It provides a historical overview of scientific arguments against the idea of multiple inhabited worlds and discusses their relevance to current scientific and popular perspectives.

Findings

Historical scientific challenges to pluralism

Persistence of the idea despite scientific objections

Implications for future scientific and public understanding

Abstract

This paper provides an overview of recent historical research regarding scientifically-informed challenges to the idea that the stars are other suns orbited by other inhabited earths -- an idea that came to be known as "the Plurality of Worlds". Johannes Kepler in the seventeenth century, Jacques Cassini in the eighteenth, and William Whewell in the nineteenth each argued against "pluralism" based on what in their respective times was solid science. Nevertheless, pluralism remained popular despite these and other scientific challenges. This history will be of interest to the astronomical community so that it is better positioned to avoid difficulties should the historical trajectory of pluralism continue, especially as it persists in the popular imagination.