You're probably referring to the Carrington Event https://en.m.wikipedia.org/wiki/Carrington_Event https://en.m.wikipedia.org/wiki/Carrington_Event The instru

You're probably referring to the Carrington Event https://en.m.wikipedia.org/wiki/Carrington_Event https://en.m.wikipedia.org/wiki/Carrington_Event The instruments to measure the strength of solar flares didn't exist, but I think it's estimated between X40 to X50. For comparison, last may the strongest flare was X8.7 https://en.m.wikipedia.org/wiki/May_2024_solar_storms https://en.m.wikipedia.org/wiki/May_2024_solar_storms