Red Lights in an Ancient Sky: Medieval Solar Storms Revealed by Trees and a Poet’s Diary

Space scientists link a medieval solar proton event (roughly 1200–1204 CE) to red auroras seen at mid-latitudes, using carbon-14 in buried Japanese asunaro trees and the Meigetsuki diary to date the phenomenon; dendroclimatology shows the sun’s cycle was unusually short (7–8 years) during that period, indicating a powerful yet sub-extreme space-weather episode, reported in 2026.