A disruptive solar storm, large enough to cause a significant disruption in our electronic and network systems, occurs on average once every 25 years, researchers have recently discovered.
By analyzing the magnetic field records at opposite ends of the Earth (the United Kingdom and Australia), scientists at the University of Warwick and the British Antarctic Survey have been able to detect superstorms that date back over a period spanning back one hundred and fifty years.
The find was possible thanks to a new method of analyzing historical data, instated by the University of Warwick, of the last 14 solar cycles, long before the space age began in 1957, instead of the last five solar cycles currently used.
Surprisingly, the researchers discovered that “severe” magnetic storms occurred in 42 of the last 150 years, and “large” superstorms occurred in 6 of 150. Generally, a storm can last only a few days, but it can be very harmful to modern technology.
Superstorms can cause blackouts, disrupt satellites, interrupt aviation and cause temporary loss of GPS signals and radio communications.
Lead author Professor Sandra Chapman of the Fusion, Space and Astrophysics Center at Warwick University said in a statement: “These super-storms are rare events but estimating their chance of occurrence is an important part of planning the level of mitigation needed to protect critical national infrastructure.”
“This research proposes a new method to approach historical data, to provide a better picture of the chance of occurrence of super-storms and what super-storm activity we are likely to see in the future.”
The Carrington Storm of 1859 is widely recognized as the largest superstorm in recorded history but predates even the data used in this study.
The analysis led by Professor Chapman estimates what amplitude it would need to have been to be in the same class as the other super-storms- and hence with a chance of occurrence that can be estimated. To the surprise of researchers, they discovered that super-storms can occur far more frequently than initially thought.
“Our research shows that a super-storm can happen more often than we thought. Don’t be misled by the stats, it can happen any time, we simply don’t know when and right now we can’t predict when,” explained Professor Richard Horne, a space weather scientist at the British Antarctic Survey.
That’s why analyzing and studying space weather is so important, as it is directly driven by the sun. Although smaller solar storms are common in our solar system, from time to tome powerful, much larger solar storms take place. The larger ones could drastically impact our technology.
One of the possible ways to monitor space weather is by studying the changes that are embedded within the magnetic field and the surface of our planet.
Although we have been observing and gathering data throughout multiple stations since the start of the so-called space age, if we want to better understand space-storms and their cycles we need to go further back in time.
The scientists have discovered that the sun has, on average, an 11-year cycle of activity with variable intensity, according to data gathered since 1957. This data cover only five cycles of solar activity.
The aa geomagnetic index is gathered thanks to data from two different scientific stations located in opposite parts of the world, in order to cancel out our planet’s own background field. This data goes back over 14 solar cycles, comprising a period of approximately 150 years.
However, as explained by researchers, it has a poor resolution.
Employing year-long averages of the top few percents of the aa index the scientists discovered that a ‘severe’ super-storm happened in 42 years out of 150 (28%), while a ‘great’ super-storm took place in 6 years out of 150 (4%) or once in every 25 years. As one example, the researchers point to the 1989 storm that caused a major power blackout of Quebec, as a major solar storm.
The researchers further explain that back in 2012, our planet narrowly avoided catastrophe as a coronal mass ejection from the sun narrowly missed our planet, eventually flying off in another direction.
The researchers have revealed that had the powerful coronal ejection struck Earth, it would have been registered as a major super-storm, probably causing numerous issues in GPS systems, and satellites orbiting the planet.