Scientists solve 1840s space weather mystery

Furthermore, the authors also found contemporary newspaper accounts of Holmes delivering a lecture on chemical effects of the solar spectrum in Scotland. So Holmes was clearly interested in solar activity and was familiar with Lockyer’s discovery of helium lines in solar spectra. There is also an 1877 letter from Holmes inviting Lockyer for a visit, indicating they had a business relationship of some kind.

That still did not explain the discrepancy between the reported 1841 date for the Exeter train delay and historical records. “No citation is provided that would enable an investigation into the veracity of the statement,” Wild et al. wrote. “The remarkable claim that [the operators] ‘reported next morning that someone was playing tricks with the instruments’ hints that this account may have originated from a contemporary newspaper report or suchlike, but we have been unable to find any report that included this phrase or any language to this effect.”

Wild and his co-authors next turned to archival scientific records, specifically the earliest magnetograms recorded at the Greenwich magnetic observatory in London. There is a record of “extraordinary” observations of a magnetic field, indicating strong geomagnetic storms, as far back as 1840, but no unusual activity, like aurora, was reported in England for October 18, 1841. However, there was strong geomagnetic activity around October 18, 1848, confirmed in contemporary newspaper accounts and by sunspot observations made by British astronomer Temple Chevallier on October 19, 1848.

When Wild et al. consulted contemporary railway timetables, they found references to a 10:05 pm express train departing from Exeter between March 11, 1848, and July 26, 1849. They suggest that the original 1841 date mentioned in the Nature paper was a typographical error and that the event occurred but the year was wrong. With the 1841 account ruled out, the earliest documented example of space weather affecting technology is a March 1847 incident involving “spontaneous electrical currents” disrupting the telegraph systems on the Midland Railway, as a “brilliant aurora” glowed in the British Isles.

Space Weather, 2026. DOI: 10.1029/2026SW005239  (About DOIs).