For thousands of years, people have gazed at the vivid auroras dancing in the night sky. But these beautiful displays are more than just a pretty sight. They are a warning sign of a hidden danger – geomagnetically induced currents.
The auroras are caused by particles from the sun crashing into the Earth’s magnetic field. These same forces can compress the magnetic field, resulting in huge currents that can reach the ground.
New research shows that the angle at which these solar flares hit the Earth is critical to protecting infrastructure.
“Auroras and geomagnetically induced currents are caused by similar drivers of space weather. The aurora is a visual warning that electric currents in space can generate these geomagnetically induced currents on earth,” explained Danny Oliveira of NASA’s Goddard Space Flight Center and lead author of this new study.
Frontal blows
Earth’s dazzling auroras result from two processes: solar storms unleashed by the sun, and magnetic field compressions caused by interplanetary shocks. These shocks occur when a fast solar wind overtakes a slower flow, thereby creating a shock wave.
Both can cause dangerous currents to flow through the Earth, potentially damaging electrical infrastructure. Bigger events carry greater threats, but even minor shocks carry risk.
“The auroral region can significantly expand during severe geomagnetic storms,” Oliveira added. “Normally its southernmost limit is around 70 degrees latitude, but during extreme events it can drop to 40 degrees or even more, which certainly happened during the May 2024 storm – the worst storm over the past two decades.”
The researchers found that head-on impacts are likely to create the strongest geomagnetically induced currents, leading to “powerful electrical currents at ground level, threatening pipelines and submarine cables.”
This is because head-on shocks can compress the magnetic field more.
How the angle is found
The researchers studied how the angle and timing of solar strikes affect geomagnetically induced currents. To understand the relationship, the researchers looked at two sets of data.
One was a collection of recorded interplanetary impacts, while the other was readings of electrical currents taken from a natural gas pipeline in Mäntsälä, Finland. This pipeline is located in a region that often sees auroras during times of strong solar activity.
They used the interplanetary magnetic field and solar wind data to calculate the angle and speed of each impact. And then he divided them into three categories: strongly inclined, moderately inclined, and almost frontal.
Research shows a clear relationship between the angle of impact and the strength of the current. The more frontal a solar strike hits, the stronger the shock of electricity traveling to earth. This electrical surge usually occurs in two bursts: one immediately after the initial shock and another during a subsequent substorm—a smaller geomagnetic disturbance. Surprisingly, these peak waves were strongest at midnight, when Mäntsälä’s north pole faces directly toward the sun.
The study authors claim that scientists can predict the angle of impact up to two hours before impact. This can provide time to take precautions, such as reducing power on certain lines.
“Although Mäntsälä is in a critical location, it does not provide a world picture. In addition, the data from Mäntsälä are missing several days in the investigation period, which forced us to discard many events in our shock database. It would be nice if the world’s energy companies made their data available to scientists for research,” Oliveira concluded in the press release.
The findings are published in the journal Frontiers in Astronomy and Space Sciences.
FOR THE EDITOR
Mrigakshi Dixit Mrigakshi is a science journalist who enjoys writing about space exploration, biology and technological innovation. Her professional experience spans both broadcast and digital media, allowing her to learn a variety of storytelling formats. Her work has been featured in well-known publications including Nature India, Supercluster and Astronomy magazine. If you have any suggestions in mind, please feel free to shoot her an email.
