I know that I am mortal by nature, and ephemeral; but when I trace at my pleasure the windings to and fro of the heavenly bodies I no longer touch the earth with my feet: I stand in the presence of Zeus himself and take my fill of ambrosia.

Claudius Ptolemy, c. AD 100 – c. AD 170
(talking about other gyrating bodies)

Responsible organizers: Iván Calvo, José Luis Velasco, J. Arturo Alonso (CIEMAT) and Félix I. Parra (University of Oxford).

Photo by Felipe Gabaldón