This stunning engraving is an early view of the sun shown with solar flares and surface eruptions based on the observations of Kircher and Christoph Scheiner in 1635. Kircher's masterpiece, titled Mundus subterraneus (The Underground World) was the first serious effort to describe the physical makeup of the earth, proposing theories (sometimes fantastic) in the areas of physics, geography, geology, and chemistry.
References: De Vorsey (Mercator's World) Vol. 8 No. 2, pp. 28-31.