A super solar storm rocked Earth in 1872; they’re more common than you think
The Washington Post December 3, 2023
Around 11:30 p.m. on Feb. 4, 1872, the sky above Jacobabad suddenly brightened, as if a portal to heaven had opened. A passerby watched in amazement and terror, while a pet dog became motionless, then trembled. The godly glow morphed, from red to bright blue to deep violet, until morning.
Electric communication cables mysteriously glitched in the Mediterranean, around Lisbon and Gibraltar, London and India. Confused telegraph operators in Cairo reported issues in sending messages to Khartoum. One incoming message asked what was the big red glow on the horizon — a fire or a faraway explosion?
The source was in fact 90 million miles away. A surge of particles from our fiery sun bombarded Earth’s upper atmosphere, generating a geomagnetic storm that painted skies and disrupted electric systems.
Now, newly uncovered data show that this February 1872 event ranks among the top three greatest geomagnetic storms to hit Earth on record. The findings reveal that these large events — super geomagnetic storms — are more common than researchers previously realized, posing a major risk if one hit today’s technology-heavy society.
“The intensity of the solar geomagnetic storm was excessively large and possibly one of the largest,” said Hisashi Hayakawa, the study’s lead author. “Such a strong geomagnetic storm would completely mess up modern civilization.”
Storms that are off the charts
The most intense super geomagnetic storm is said to be the Carrington Event in September 1859, named after the British astronomer who helped shed light on it. The storm brought glowing lights, or auroras, as far as Tahiti — a major surprise since most aurora congregate around Earth’s poles. Spikes of electricity paralyzed the world’s telegraph systems, halting messages.
The Carrington Event was thought to be a one-of-kind, freak occurrence, but scientists are learning that is not true.
Another super geomagnetic storm occurred in May 1921, the largest geomagnetic storm of the 20th century. The storm, sometimes referred to as the New York Railroad storm, brought spectacular nighttime aurora. It also interrupted and damaged telephone and telegraph systems linked to railroad systems in New York City and around the state.
Now, the new study adds a third storm — from February 1872 — to the geomagnetic hall of fame, ranking as intense, if not more intense, than the others by some measures. The storm pushed aurora even farther south than the Carrington Event, causing magnetic disturbances on Earth equal to or worse.
“Some of the colors that are mentioned in this event in terms of auroral coloring and then the behavior, in my mind, are even more explicit than what was documented in the [Carrington] event,” said Delores Knipp, co-author and space physicist at the University of Colorado at Boulder. “It is likely that the level of magnetic disturbance or perturbation is every bit as large as the Carrington Event.”
Searching for geomagnetic clues from the past
Analyzing an event that you didn’t witness in person takes a bit of detective work.
Formal scientific observations of the event were limited in 1872, but researchers found upward of 700 reports of the event from overlooked sunspot records, magnetic field records, newspaper clips, telegraph operators, ship records and whatever else was available.
Using the documents, Hayakawa and his colleagues at the U.S. National Solar Observatory and the Royal Observatory of Belgium assessed the storm’s intensity, duration and origin. They also reconstructed the conditions to see how far the aurora probably extended during the storm. The study took around six years to complete.
The aurora was spotted in very unusual places close to the equator. A telegraph operator in Mumbai reported strong earth currents at 7:30 p.m. on Feb. 4, 1872, until 7 a.m. on Feb. 5, with the aurora plainly visible from 8:30 p.m. to 4:30 a.m. A news article stated the “aurora was brilliant in the extreme” in Aden. A bright arc was reported in Shanghai.
“It was certainly surprising for scientists, as well, because India is far away from that magnetic pole,” said Hayakawa, a space physicist at Nagoya University in Japan. “Generally, in order to expand the auroral oval, that geographic area, we need a stronger geomagnetic storm.”
But the origin of the massive storm was rather modest. Analyzing sunspot records, the team found the storm probably originated from a medium-size sunspot group. Extreme geomagnetic storms typically come from huge sunspots.
“Even though they’re not perhaps all that large, the real thing that matters is the complexity” of the sunspot region, Knipp said. She said it is concerning that such an intense storm was created from a moderate sunspot group, but agencies across the world are helping to track and study these triggers on the sun — before they hit Earth.
Another hit coming soon?
Three super geomagnetic storms in the last two centuries may not seem like a lot, but researchers say that’s too frequent for comfort.
Space physicist Dan Baker, who was not involved in the research, said he is surprised to see another incredibly intense storm occurring relatively soon after the famed Carrington Event. He said the February 1872 event “adds to the sense that major, highly disruptive solar events and resulting geomagnetic storms are more prevalent than most people assume.”
“If the sun is producing Carrington Events or greater disturbances essentially every solar cycle or even every other solar cycle, then we had better sit up and take notice,” said Baker, director of Laboratory for Atmospheric and Space Physics at the University of Colorado at Boulder.
In fact, such a super geomagnetic storm narrowly missed Earth in July 2012. A lot of media didn’t cover the potentially devastating event, but the storm was the most powerful in more than 150 years.
A storm that size would cause a lot of issues on modern society, said Hayakawa. It would knock out energy, communication and satellite systems, which we’ve become so accustomed to in our daily lives.
Yet the occurrence of such an event is still rare, he said. Several parameters need to line up: The sun needs to emit a fast eruption, the sun’s and Earth’s magnetic fields need to link up just right, and the storm needs to be very large. Then, it needs to be directed toward Earth.