On the 22nd of June in the year 1530, the sky above Venice turned into a most peculiar shade of green. Citizens of the famous city-state spilled out of their homes and churches with looks of absolute bewilderment, gazing up at the bizarre color that had overcome the heavens.

Reports quickly spread that this strange phenomenon was being seen all across the surrounding regions as far as Padua and Treviso. Local clerics were at a loss to explain the event and feared it may be an ill omen. But the elderly scholar Galvani, known for his keen interest in all things astronomical, had a hypothesis. After ushering patrons at his favorite tavern to the door so he might examine the oddity directly, Galvani concluded this was no supernatural occurrence or sign from God.

Through his studies of comets, eclipses, and other celestial irregularities, Galvani believed he knew the true origins of this unusual green sky. As the story goes, he summoned neighbors to his side and, pointing to the north, explained that great plumes from Mount Vesuvius had carried across the skies. Winds had swept the sulfurrich smoke high above the land in concentrations dense enough to obscure the sun's light and color the heavens with its hue. The elder's erudite explanation brought relief and even admiration to those who had initially been so unsettled.

By nightfall, the green tint had started to fade as the wafting plumes dispersed. But Galvani's accurate deduction brought him praise that echoed far beyond the borders of the floating city. It marked the first known incident where man attributed an atmospheric event, and not supernatural forces, to the emissions of our geologic companion —Mother Nature. Not a bad day's work for an pioneering intellect, even if the sky looked far less than normal in the process.