It has long been recognized that astronomy was a catalyst of the Scientific Revolution, spurring on deeply consequential speculation about the nature of the cosmos and its physical principles. Yet the history of celestial physics is far richer than was thought a generation ago, and there is much to be learned about the origins of the field, particularly in the sixteenth century, when humanist activity brought forth a dazzling array of philosophical possibility—from reconsiderations of Aristotle and Islamicate comm…