Imagine a long and challenging ascent of a mountain peak towards the end of the day with the sun nearly set. Emerging above the clouds to reach the summit, the climber looks down to see on the clouds below, a colossal figure crowned with a wreath of glorious colour, even with multiple rings. This figure seems to be related to the climber’s shadow, but can also shift on its own as if in a cauldron. This could be interpreted as rapturous, divine, or satanic. Those who first witnessed this phenomenon in the Harz Mountains in Germany called it the “Brocken Spectre” (cover image), and it was viewed with a sense of malevolence and foreboding. It was often believed to be present as part of a witch’s brew. Yet, others would view it with divine significance, believing they had been touched with a crown by God.

Surely such a complex subtle meteorological event would have been beyond the understanding of people hundreds or thousands of years ago. We know that Olympiodorus, one of the chief Aristotelian commentators, who taught at Alexandria in the 6th century and was one of the …