A new study shows that the brilliant auroras dancing across the night sky warn of a potential danger: geomagnetically induced electric currents.
Auroras are created by charged particles from the Sun hitting Earth’s magnetic field. The force of the collision can compress the field, creating huge electric currents that reach the ground. According to new research led by Denny Oliveira of NASA’s Goddard Space Flight Center, the angle of impact is important for protecting infrastructure.
“Auroras are a visual warning sign that electric currents in space can generate geomagnetically induced currents,” Oliveria said.
The two processes that create auroras on Earth are solar storms and the compression of the magnetic field by interplanetary shocks (as fast-moving solar wind overcomes slower wind, creating shock waves). Both have the potential to send electrical currents through the Earth that could damage electrical infrastructure.
“The aurora can easily expand significantly during severe geomagnetic storms. Normally its southernmost boundary is at latitude 70, but in extreme events it can extend to latitude 40 or even further, as happened during the geomagnetic storm in May 2024,” Oliveria noted.
The research team noted that the head-on collision compresses the Earth’s magnetic field so violently that it creates the strongest geomagnetic induction current, threatening underground pipelines and cables.
They looked at two sets of data to draw their conclusions. One was a record of interplanetary shocks, and the other was electrical current data taken from a gas pipeline in Mantsala, Finland. The pipeline is located in an area where auroras are often seen during periods of high solar activity.
Magnetic field and solar wind data helped calculate the angle and speed of the impact. The impacts were then divided into high-angle, moderate-angle, and near-head-on. The study found a clear relationship between angle and current intensity. The closer the impact was to head-on, the stronger the current that traveled to the ground. The strongest oscillations occurred at midnight when the north pole of Mantsala faced the Sun directly.
According to the research team, scientists can predict the angle of impact two hours in advance, thereby giving infrastructure management units time to deploy preventive measures such as reducing power on certain lines.
Oliveria said the phenomenon in Mantsala did not provide the full picture, and he wished that power companies around the world would provide data for more thorough research.