We have two hours to protect the power grid from a major solar storm. The May dawns proved it.

A powerful geomagnetic storm on May 10 blanketed half the planet in auroras. Scientists are still studying the event to try to predict the next Carrington event — a solar impact so strong it could cause catastrophic damage to the power grid.

The auroras are more than just a visual spectacle. This celestial dance of green and red lights occurs when the Earth’s magnetic field interacts with charged particles from the Sun.

During a solar storm, the Sun ejects large amounts of plasma along paths that can collide with Earth. When these particles reach Earth’s magnetosphere, the magnetic field that protects us directs them toward the poles, where they collide with gases in the atmosphere, oxygen and nitrogen, producing light.

If a solar ejection, called a coronal mass ejection, is very strong, it can compress the magnetosphere, reducing its size on the dayside of the Earth (the side facing the star) and causing magnetic field lines to become smaller and connect at lower latitudes than usual, which can cause auroras in those regions.

Warning of threat to electrical networks. Auroras also serve as warnings of imminent threats to our electrical infrastructure. And a powerful event in May helped scientists better predict the level of risk thanks to the angle of the sun.

In particular, a team of NASA researchers found that solar storms that collide with Earth’s magnetic field can cause more intense geomagnetic currents, similar to those that set some telegraph lines on fire in 1859.

The study, led by astrophysicist Denny Oliveira of NASA’s Goddard Space Flight Center, was published in the journal Frontiers in Astronomy and Space Sciences and warns of how these solar strikes could overload and damage not only the electrical grid, but all types of infrastructure with some conductivity, such as gas pipelines.

Measurements on a gas pipeline in Finland. Oliveira’s team compared solar storm data with measurements of geomagnetically induced currents in a gas pipeline in Mäntsälä, Finland.

Their research showed that solar particles hitting the Earth’s magnetic field at an angle produce less intense currents than head-on collisions, because head-on collisions compress the magnetic field more strongly, generating more powerful currents.

One reason the scientists chose Mäntsälä is the openness of its data, but the general lack of information led them to rule out many correlations with solar shocks. “It would be good if energy companies around the world would make their data available to scientists to study,” Oliveira said in a press release.

Two hours to protect our infrastructure. More data would mean more knowledge about how long it takes for a solar storm to generate a geomagnetic current. With the data available, the good news is that head-on collisions are not only more powerful, but also more predictable, thanks to telescopes that are always pointed at the Sun.

It’s not a threshold worth writing home about, but the study says they can be predicted two hours in advance, opening a crucial window for taking protective measures on power grids and other infrastructure, such as the aforementioned gas pipelines.

“One thing that electrical infrastructure operators could do to protect their equipment is to only operate certain specific electrical circuits when a discharge warning is issued,” explains Oliveira. “This would prevent geomagnetically induced currents from shortening the life of the equipment.”

Image | Ben (CC BY-ND 2.0)

In Hatake | Sunspot 17 times bigger than Earth sparks red auroras over half the globe in rare event