A Japanese poet wrote in his diary that "red lights" appeared in the sky over Kyoto. An analysis of tree rings suggests a powerful solar storm created the sight.

An ancient solar storm left clues in tree rings and a famous poet's diary: 'Red lights in the northern sky'

Source: space
Source Link: https://www.space.com/stargazing/auroras/an-ancient-solar-storm-left-clues-in-tree-rings-and-a-famous-poets-diary-red-lights-in-the-northern-sky