A medieval poet and some buried trees have just revealed something very strange about the 13th-century Sun

Researchers tied a 1204 Japanese poem about red lights over Kyoto to evidence of a brief, unusually intense solar cycle in the early 13th century.

Tree-ring data from buried trees in northern Japan helped confirm the timing of the event and its extreme solar activity.

The findings suggest auroras may have been seen far from the poles during that period.

The study shows how historical texts and natural archives can be combined to reconstruct past solar behavior and its Earth impacts.