At the Crossover between Physics, Mathematics, Astronomy and History: a Didactic Proposal on Römer's Measure of the Speed of Light

This contribution discusses the role of mathematics and history of science in physics education. Römer's experiment is interesting because it was part of the historical debate between the two conceptions of instantaneous propagation and finite speed of light. Moreover, studying it more closely than textbooks normally do forces the use of unobvious mathematic tools adaptable to different educational levels. The subject is presented with questions and suggestions regarding the relative movements of the four stars concerned (Sun, Earth, Jupiter, Io) and the occultations and eclipses of Io. Cabri software is used for pictures and animations, and astronomical tables for time calculations.