The Earth has in recent months faced various geomagnetic storms. However, they remain minor if we compare it to the Carrington event of 1859 which is the most powerful solar storm ever recorded. And yet, we might have underestimated it. Recent research has in fact revealed that the disruption of the Earth's magnetic field during this event was even greater than expected. This discovery highlights the potential vulnerability of modern society to such events.
A historic storm
On September 1, 1859, a spectacular scene took place in the earth's sky. The Sun, this star which seems so stable, suddenly decides to release an incredible amount of energy. Jets of electrified gas and subatomic particles rocket at dizzying speed into space while straight to our planet.
This massive discharge, equivalent to the colossal energy of ten billion atomic bombshits the Earth with incredible force. The consequences are immediate and devastating. Telegraph communications, then at their peak, were the first to suffer the shock. Telegraph lines, although renowned for their reliability, suddenly go out of control, sending sparks and electric arcs in all directions.
Meanwhile, in the night sky, an extraordinary spectacle unfolds. Northern lights, usually confined to the polar regions, begin to dance across the sky and reach latitudes never before observed. Surprised witnesses report seeing these colorful glows as far away as Cuba and Hawaii.
The magnitude of these auroras is such that some residents can read newspapers in the light of these celestial phenomena transforming the night into a spectacle worthy of fairy tales. However, behind this beauty lies the brutal reality of the massive disruption caused by the solar event.
Fires broke out in telegraph stations, the wires became incandescent under the effect of the unleashed electricity. The operators, accustomed to handling messages with precision, are shocked by the sudden violence of these uncontrolled flames.
Understanding the phenomenon
The Carrington eventnamed after the astronomer Richard Carrington who first observed it, will go down in the annals of history. This solar storm, the most powerful on record, is a testament to the Sun's impressive ability to influence our world in ways we can't always predict or understand.
That being said, despite the frequent occurrence of solar storms throughout Earth's history, our data on their magnitude is limited, dating back less than two centuries. The Carrington event indeed occurred at a time when observations were still primitive. THE magnetograms British observatories at Greenwich and Kew, which measured fluctuations in the Earth's magnetic field, were among the few tools available.
However, recent technological advances have opened up new perspectives to better understand the real impact of the Carrington event on Earth. Among these advances, the digitization of historical magnetograms has proven to be a valuable resource for researchers. They were originally designed to measure fluctuations in the Earth's magnetic field, but they were far from prepared to record a geomagnetic storm of such magnitude as that of the Carrington event. However, thanks to advances in modern digitization, these records have been able to be preserved and analyzed in detail, revealing crucial information about the nature and scale of this historic event.
An event more intense than expected
The analysis of these magnetograms highlighted extraordinary and rapid movements in the Earth's magnetic field which were estimated at a remarkable speed of 500 nanoteslas per minute. To put this into perspective, it is important to note that geomagnetic storms, which occur once a century, are generally associated with changes of the order of 350 to 400 nanoteslas per minute at the latitude of London, which makes the Carrington event estimates even more impressive.
These new results suggest that the event was much more intense than initially estimated. The rapid and massive movements of the Earth's magnetic field, as revealed by digitized magnetograms, far exceed what was previously thought possible.
This discovery thus challenges our previous knowledge about the magnitude of solar storms and highlights the importance of better understanding these phenomena to prepare and protect our modern society against such events in the future. And for good reason: if such a storm occurred today, the consequences could be devastating.
In response to these findings, experts are calling for increased vigilance and preparedness efforts for the risks posed by solar storms. New strategies for protecting critical infrastructure, such as communications networks, power distribution systems and orbiting satellites, are being considered. Internationally, initiatives are underway to improve the resilience of modern systems to these events, including controlled outage protocols and enhanced protection against electromagnetic fluctuations. These measures, although still embryonic, could play a crucial role in preserving our society in the event of a solar storm of similar intensity to that of the Carrington event.
Details of the study are published in Space Weather.
