Talk on Picturing the Planets by Susan Cartwright
The planets – literally, from the Greek, “wanderers” in the night sky – have been the subject of study throughout the course of human history. Before the era of street lighting, the patterns of stars in the night sky, and the fact that a few of the brightest “stars” did not stay in these fixed patterns but instead moved across the sky over the course of the year, would have been very noticeable to anyone who spent much time outside after dark. Many cultures embedded the movement of the planets into religion, calendars or astrological predictions, and developed quite sophisticated models for describing their motions, but it was not until the ancient Greeks that anyone seems to have tried to produce a physical model, as opposed to a set of mathematical formulae. In this talk I will try to explain how our picture of the planetary system has changed over the course of human history, and why it still remains a live subject of research today.