You might say it was a bit shocking when sensors at the Polarlightcenter in northern Norway picked up electrical currents flowing through the ground on the evening of January 6.
The center, which is dedicated to the study and observation of the aurora borealis, or “northern lights,” also maintains a number of sensors and instruments to measure the electromagnetic forces that create the brilliant displays, but can also have other impacts on our planet’s surface.
“It seemed to be some kind of shockwave,” the center’s Rob Stammes told Spaceweather.com’s Dr. Tony Phillips. “My instruments detected a sudden, strong variation in both ground currents and our local magnetic field. It really was a surprise.”
Phillips, himself an astronomer who has done much work for NASA and elsewhere on space weather, notes that just before the surge was seen in Norway, NASA detected a 180-degree swing in the interplanetary magnetic field near Earth and the density of the solar wind quintupled.
“Earth may have crossed through a fold in the heliospheric current sheet—a giant, wavy membrane of electrical current rippling through the solar system. Such crossings can cause these kind of effects,” he wrote.
Another way to think of this is to imagine the earth as a beach ball floating through ripples and waves on the surface of the lake. It’s not a perfect metaphor, but think of the spray from the waves as the energetic particles raining down on our atmosphere in the form of aurora. When the wave action is particularly dramatic, the spray might even cause the surface of the ball itself to vibrate, like the electrical current picked up in the Norwegian soil.
The notion of electrical surges from space brings up the specter of solar storms that have caused power outages and could threaten to wreak havoc with our technologically-dependent society at some point in the future.
Fortunately we were dealing only with the relatively normal background electrical current passing through the solar system. Rather than knocking out power and communications, the surge seen January 6 was still most easily observed in the sky.
Indeed, the same evening that the dirt was electrified in Norway, the aurora was out in full force in the sky above.
“We couldn’t see the auroras in northern Norway because of cloud cover,” Stammes tells Phillips. “We had to be satisfied with the electricity underfoot.”