By Parandis Tajbakhsh In 2018, the Transiting Exoplanet Survey Satellite (TESS) began its two-year mission searching for extrasolar planets, orbiting around 200,000 stars located within 300 light-years of the Earth. TESS followed in the footsteps of NASA’s Kepler Space Telescope, launched in 2009to find Earth-sized or smaller planets around other stars and to estimate the fraction of stars in our galaxy that host Earth-sized planets. While the scientific endeavour to find other habitable planets is still in its infancy, the history of speculations about the existence of life beyond Earth is much more ancient. Despite extensive research in this field, at least within the West and the Christian world, the ‘history of extraterrestrial life debate’ has remained less well known. This post discusses some of the major events that have shaped the ‘plurality of the worlds debate’ throughout the centuries.