A Recent Study Reveals Increased Frequency of Solar Superstorms

A depiction of the Northern Lights over Okazaki, Japan on February 4, 1872, is courtesy of Shounji Temple and has been enhanced for contrast. Credit: Shounji Temple

In November, the aurora borealis, or northern lights, were observed unusually far south, including in places like Italy and Texas, due to a solar coronal mass ejection impacting Earth’s magnetic field and atmosphere. This incident pales in comparison to the massive solar storm that occurred in February 1872.

This event in 1872 led to global auroral displays, even visible near the equator in cities like Bombay and Khartoum. An international research team from nine countries recently completed a thorough study of this major historical event, tracing its solar origins and its extensive effects on Earth.

The 1872 storm significantly disrupted telegraph communications. In today’s world, where we heavily rely on technology, a similar storm would pose a severe threat to power grids and satellite communications. The research confirms that such extreme storms are more frequent than previously believed.

Modern Vulnerability to Solar Storms

Our modern society’s reliance on technological infrastructures like power grids, communication systems, and satellites makes us particularly susceptible to large geomagnetic storms.

Designated Assistant Professor Hayakawa, the study’s lead author, warns that the longer a power outage lasts, the more challenging it would be for urban societies to manage. He suggests that in a worst-case scenario, such storms could disrupt power grids, communication systems, airplanes, and satellites, posing the question of how life could be sustained without such infrastructure.

Solar flares and coronal mass ejections on the sun are a result of “magnetic reconnection”—a process involving the merging, reconnection, and snapping apart of magnetic field lines, leading to explosions that release vast amounts of energy. Credit: NASA Conceptual Image Laboratory

Such extreme storms are rare. However, recent studies highlight two significant events: the Carrington storm in September 1859 and the New York Railroad storm in May 1921. This new research adds the February 1872 Chapman-Silverman storm to this list of extreme events.

During the 1872 storm, technological infrastructure was significantly affected, even in tropical regions. Telegraph communications along the Indian Ocean submarine cable between Bombay (Mumbai) and Aden were disrupted for hours, with similar disturbances reported on the Cairo-Khartoum landline.

In-Depth Analysis by an International Team

The research was conducted by a multidisciplinary team of 22 scientists led by Nagoya University in Japan (Hisashi Hayakawa), the US National Solar Observatory (Edward Cliver), and the Royal Observatory of Belgium (Frédéric Clette). The team utilized historical records and modern techniques to evaluate the Chapman-Silverman storm from its solar origin to its impact on Earth.

For the solar origin, the team reviewed largely forgotten sunspot records from historical archives, particularly Belgian and Italian records. To assess the storm’s terrestrial impacts, they used geomagnetic field measurements recorded in diverse locations like Bombay (Mumbai), Tiflis (Tbilisi), and Greenwich, as well as hundreds of accounts of visual auroras in various languages.

A Belgian sunspot drawing depicting the solar surface on February 3, 1872. Credit: Royal Astronomical Society (RAS MS Bernaerts, v. 3, f. 26)

An intriguing aspect of the 1872 storm was its likely origin in a medium-sized but complex sunspot group, as confirmed by Belgian and Italian solar records. This indicates that even a medium-sized sunspot group can trigger one of the most extreme magnetic storms in history.

Comprehensive Research on Historical Aurorae

Hayakawa and his team expanded their study of historical aurorae by examining records from libraries, archives, and observatories worldwide, identifying over 700 auroral records. These records showed that the night sky was illuminated with magnificent auroral displays from the polar regions to the tropics.

“Our findings confirm the Chapman-Silverman storm in February 1872 as one of the most extreme geomagnetic storms in recent history, rivaling the Carrington storm in September 1859 and the NY Railroad storm in May 1921,” Hayakawa stated. He emphasized that the occurrence of at least three geomagnetic superstorms in the last two centuries highlights a significant risk to modern society and underscores the importance of preserving and analyzing historical records to assess, understand, and mitigate the impact of such events.

Hayakawa noted that while such extreme events are rare, their occurrence within a short time span indicates a real threat to modern society. He stressed the importance of preparing for enhanced auroral activity as the Sun approaches the maximum of Solar Cycle 25, predicted for 2025.

Reference: “The Extreme Space Weather Event of 1872 February: Sunspots, Magnetic Disturbance, and Auroral Displays” by Hisashi Hayakawa, Edward W.

Frequently Asked Questions (FAQs) about Solar Superstorm Research

More about Solar Superstorm Research

• Understanding Solar Superstorms: The 1872 Event
• Risks of Technology Dependency on Solar Storms
• History and Analysis of Geomagnetic Disturbances
• Sunspot Records and Solar Storm Research
• The Implications of Solar Cycle 25