A TRAWL through two ancient texts written almost a thousand years ago has
unearthed a link between sunspots and an aurora sighted at roughly the same time
on opposite sides of the Earth. The link shows that solar activity hit a peak in
1128, and lends credence to the observations of medieval astronomers.
Richard Stephenson, a physicist from the University of Durham, noticed a
picture of sunspots in The Chronicle of John of Worcester, a diary kept
by an English archivist in the Middle Ages. The drawing shows the Sun with two
black dots encircled with brown and red rings.…
