Adam Smith's account of commercial societies as societies of strangers may be read as a moral defense of commercial societies. A society of strangers can be a fostering environment for moral development. Smith's account of moral development echoes his contemporaries' accounts of the move from geocentric to heliocentric understandings of the solar system. If we imagine ourselves at a distance from our own position, we humble the arrogance of our self-love as we realize we are not the center of the universe. In The Theory of Moral Sentiments, Smith describes the realization that we are not the center of the moral universe. In contemporary presentations and popularizations of astronomical theories the realization is that literally we, on Earth, are not the center of the physical universe. Adam Smith's theory of moral development, and therefore his moral defense of commercial societies, seems indebted to astronomical theories in general, rather than just to Newton, as it is commonly assumed.