A 178-year-old mystery surrounding one of the earliest recorded examples of space weather affecting technology has been solved by an international team led by Lancaster University.
The first practical electric telegraph networks were deployed during the 1840s, and as solar activity increased during the following years, Victorian telegraph operators began to experience unexplained electrical effects caused by geomagnetic disturbances.
Professor Jim Wild from Lancaster University with scientists from the British Geological Survey, Natural Resources Canada, Baylor University, RMIT University, and STFC RAL Space, re-examined a widely cited account of a train delay in Exeter that was reportedly caused by geomagnetic disturbance from the sun interfering with railway's telegraph systems.
The event has previously been cited as potentially the earliest recorded example of space weather affecting human technology but the team's research published in the American Geophysical Union journal Space Weather contradicts this assumption.
The original account described how the 10:05pm train departing Exeter in Devon was delayed by 16 minutes when a "very intense magnetic disturbance" interfered with electric signalling telegraph equipment used to determine whether the railway line ahead was clear.
However, the researchers found a critical problem - the railway line referenced in the account did not open until 1846, almost five years after the alleged 1841 incident. Their investigation shows that the incident most likely took place on 18 October 1848, rather than 18 October 1841 as stated in an influential article published in Nature in 1871.
To uncover what really happened, the team combined evidence from railway timetables, historical newspapers, solar observations, auroral reports and digitised geomagnetic records. Their investigation identified a strong geomagnetic disturbance on 18 October 1848, alongside reports of sunspots and aurora seen across the UK and Europe, providing compelling evidence that the date in the original account was a typographical error.
The findings show that while the Exeter incident remains one of the earliest documented examples of space weather disrupting technology, it was not the first. The earliest credible report currently known is interference with telegraph systems on the Midland Railway in March 1847.
Professor Jim Wild, from Lancaster University's School of Physics and Astronomy and lead author of the study, said: "Space weather is often discussed as a modern challenge because of our dependence on technologies such as satellites, communications systems and electricity networks. What this study shows is that society has been experiencing the effects of space weather on technology for almost as long as electrical technologies have existed.
"The Exeter train delay is a fascinating story because it sits right at the point where emerging technologies first began to encounter the realities of the space environment. By combining historical archives with scientific observations, we've been able to show that the event almost certainly happened in 1848 rather than 1841.
"Although this means it is not the earliest recorded space weather impact, it remains one of the first clear examples of solar activity disrupting critical infrastructure. It also demonstrates the value of combining scientific records with contemporary newspaper reports and archival documents when reconstructing historic space weather events."
Dr Mike Hapgood, Visiting Scientist and Space Weather Expert at STFC's RAL Space, said: "Our research has a hint of a detective story - piecing together a wide range of archived records to better understand a historically severe space weather event. It highlights the importance of preserving these older records, which give us the evidence base we need to interpret past events and strengthen future predictions."
Nearly two centuries later, railways and other critical infrastructure remain vulnerable to space weather, although through very different technologies including power systems, signalling equipment, satellite navigation and communications networks.
Professor Wild said: "What this research highlights is that space weather is not a new threat but a long-standing natural hazard. The technologies affected have evolved from railway telegraphs to satellites, communications networks and power systems, but the challenge remains the same: understanding the risk and ensuring society is resilient to its impacts."
Dr Hapgood said: "While today's space weather capabilities are far more advanced than anything available in the 1800s, the modern technologies we depend on are also much more vulnerable to solar storms. Deepening our understanding of these events is essential for preparing for, and mitigating, the impacts of space weather - especially as we look forward to a decade of exciting space developments that will face the challenge of a new solar cycle in the 2030s."
