Something happened in year 774 that was so powerful we can measure the radioactivity in old tree rings. Best guess is a solar flare, 10 times more powerful than the Carrington Event in 1859 that zapped telegraph wires.
Worth considering the effect of the next one.
Details:… pic.twitter.com/jfFRHbDwsL

— Chris Hadfield (@Cmdr_Hadfield) February 14, 2025