One of the rarest and least understood weather events ever encountered was described as a “marvelous sign” by a 12th-century Benedictine monk.
One day, while reading through Gervase of Canterbury’s 12th-century Chronicle, a British historian stumbled upon a most unusual description of a weather event that occurred in the year 1195 AD. It read:
On the 7th of the ides of June around the sixth hour [noon], a marvelous sign descended near London. For the densest and darkest cloud appeared in the air, growing strongly with the sun shining brightly all around. In the middle of this, growing from an uncovered opening like the opening of a mill, I know not what [was the] white color [that] ran out. Growing into a spherical shape under the black cloud, [it] remained suspended between the Thames and the lodgings of the bishop of Norwich. From there a sort of fiery globe threw itself down into the river. With a spinning motion it dropped time and again below the walls of the previously mentioned bishop’s household.
After consulting with other experts, the historian now believes that Gervase was describing a rare phenomenon known as ball lightening, or mysterious orbs of light that sometimes appear in conjunction with bad weather or thunderstorms. Between a few inches to a few meters in diameter, these glowing balls of light may swoop over the landscape for as long as 10 seconds, and may even pass through glass, before disappearing.
Some scientists believe ball lightening to be composed of soil that is heated to incandescence by a cloud-to-ground lightning strike. Others theorize that bright orb is a visible manifestation of reactions involving dark matter, antimatter, or extremely tiny black holes. Or the orbs may be composed of photons of light trapped inside air bubbles produced in the intensely heated atmospheric conditions that follow a lightning strike.
Whatever the cause, this rare phenomenon remains a scientific puzzle to this day.