Unravelled, the Secret of Medieval Monk's Sketch
Byline: Richard Warburton Education Correspondent
A Midland astronomer has discovered the missing piece of a jigsaw which helps date the first illustration of sunspots - made more than 500 years before the invention of the telescope.
Dr David Willis of the University of Warwick has made a link between the Northern Lights appearing in the skies over Korea in 1128 and a drawing by a medieval chronicler, the monk, John of Worcester, in the same year.
The drawing, in The Chronicle of John of Worcester, depicts two sunspots seen on the face of the sun on December 8, 1128, plus a description of the phenomenon in Latin.
Dr Willis claims that the appearance of the Northern Lights, or aurora borealis, on December 13, 1128 over medieval Asia confirms that John of Worcester unknowingly discovered sunspots.
The link, made by Dr Willis in collaboration with Professor Richard Stephenson of the University of Durham, also proves the extraordinarily high density of solar activity during the twelfth century.
Dr Willis last nightsaid the finding has an important cultural as well scientific significance.
'From a cultural point of view, we now know this is the first ever drawing of sunspots which is amazing to consider John of Worcester logged this from sightings with the naked eye,' he said.
'It's not comparable with modern observations in the sense of satellites because people recorded what could be seen with the unaided eye, but that makes it all the more incredible. Being able to date the sunspots exactly gives us a far greater insight into how the sun has changed over the years and presents us with better information on how solar activity has appeared in the past.
'We now know solar activity was high at the end of the second and third decades of the 12th century and we can use this information to plot the effects time has played on the power and intensity of the sun.'
The sun emits gas all the time and when solar activity is high, the gases travel towards Earth and interact with the planet's magnetic field to produce spectacular atmospheric storms and the Northern Lights.
The observation in 1128 of a red light in the night sky in Songdo, the modern South Korean city of Kaesong , was recorded in the Koryo-sa , the official Korean chronicle of the time and led to Dr Willis investigating the possibility of a link with the skies over Worcester days before. …