The wheel in the sky keeps on turning.

Having recently mostly blogged about bad popular history of science and questions of historiography and methodology I thought it was time to return to writing about some real history of science. Back in 2010, I blogged about the fact that there were not just two cosmological-astronomical systems competing with each other at the beginning of the seventeenth century, as commonly believed and also falsely claimed by Galileo (Copernicus contra Ptolemaeus), but a whole menagerie of systems battling it out for ascendency till Kepler’s elliptical heliocentrism won out in about 1660. Another common misconception is that there was only one geocentric astronomical system inherited from antiquity. There were in fact several competing systems and I would now like to sketch the history of one of these systems that usually gets ignored in discussions on the subject but proved very resilient from its conception in the sixth century BCE up to the middle of the seventeenth century CE, the geocentric-geokinetic system. [To discover what that is go here]