Researchers from Durham University in Northeast England are claiming to have discovered the earliest known account of a rare weather phenomenon called ‘ball lightning’.
Usually associated with thunderstorms, ball lightning is unexplained and has been described as a bright spherical object measuring an average of 25cm, but sometimes up to several meters, in diameter.
Physicist emeritus professor Brian Tanner worked with historian professor Giles Gasper to make the connection to a ball lightning event while exploring a medieval text written several hundred years ago.
The account, by the 12th century Benedictine monk Gervase of Christ Church Cathedral Priory, Canterbury, pre-dates the previous earliest known description of ball lightning recorded in England by nearly 450 years.
The findings are published in the Royal Meteorological Society’s journal Weather.
In his Chronicle, composed around 1200, Gervase stated that “a marvelous sign descended near London” on June 7, 1195. He went on to describe a dense and dark cloud, emitting a white substance which grew into a spherical shape under the cloud, from which a fiery globe fell toward the river.
The Durham researchers compared the text in Gervase’s Chronicle with historical and modern reports of ball lightning.
Professor Tanner said, “Ball lightning is a rare weather event that is still not understood today. Gervase’s description of a white substance coming out of the dark cloud, falling as a spinning fiery sphere and then having some horizontal motion is very similar to historic and contemporary descriptions of ball lightning. If Gervase is describing ball lightning, as we believe, then this would be the earliest account of this happening in England that has so far been discovered.”
Prior to this account, the earliest report of ball lightning from England is during a great thunderstorm in Widecombe, Devon on October 21, 1638.
Medieval writings rarely survive in the author’s original version and Gervase’s Chronicle and other works now exist in only three manuscripts (one in the British Library, and two at the University of Cambridge). The Latin text was edited by Bishop William Stubbs in 1879 and there is no translation into English.
Professor Gasper added, “The main focus of Gervase’s writings was Christ Church Cathedral Priory in Canterbury, its disputes with neighboring houses and an Archbishop of Canterbury, as well as chronicling the actions of the king and his nobles. But he was also interested in natural phenomena, from celestial events and signs in the sky to floods, famine, and earthquakes.”
The researchers looked at Gervase’s credibility as a writer and a witness, having previously examined his records of eclipses and a description of the splitting of the image of the crescent moon.
Gasper said, “Given that Gervase appears to be a reliable reporter, we believe that his description of the fiery globe on the Thames on June 7, 1195 was the first fully convincing account of ball lightning anywhere.”