Scientists warn of “frontal” northern lights

“Interplanetary shocks” that hit Earth’s magnetic field head-on are something scientists must predict to protect any infrastructure that conducts electricity, according to a new study published today in Frontiers of astronomy and space science.

The appearance of magnificent green, red, purple and blue auroras – such as those seen during the global geomagnetic storm on May 10 – can signal the arrival of strong currents on Earth, potentially damaging power lines, oil and gas pipelines, railways and undersea cables.

Interplanetary shocks

An interplanetary shock – which can lead to sightings of the beautiful Northern Lights and Southern Lights – is a disturbance in the solar wind. It is caused by coronal mass ejections from the Sun. A coronal mass ejection is a cloud of magnetic fields and charged particles from the Sun that streams into space at up to 3,000 kilometers per second.

The disturbance causes Earth’s protective magnetic bubble to compress, often triggering auroras. However, the angle of impact of interplanetary shock waves is crucial for the strength of the currents, research suggests.

This is important because interplanetary shocks are much more common during solar maximum, which scientists believe is currently occurring.

Geomagnetically induced currents can damage electricity-conducting infrastructure. The stronger an interplanetary shock, the stronger the currents and auroras. If scientists can predict that an interplanetary shock will hit head-on rather than just grazing, it can help protect infrastructure from the impact, the researchers say.

Higher peaks

The study concluded that tremors that hit the Earth head-on, rather than at an angle, trigger the strongest geomagnetically induced currents. Using a database of interplanetary tremors and comparing them with measurements of geomagnetically induced currents from a natural gas pipeline in Mäntsälä, Finland – in the “aurora zone” – the scientists found that head-on tremors cause higher peaks of geomagnetically induced currents. This is because they compress the magnetic field more strongly.

They also found that the most intense peaks occurred around “magnetic midnight,” that is, the time of night (around actual midnight local time) when the North Pole is located between the Sun and Mäntsälä on the night side of the Earth.

Space weather

“Aurorae and geomagnetically induced currents are caused by similar space weather drivers,” said Dr. Denny Oliveira of NASA’s Goddard Space Flight Center, the lead author. Space weather is the flow of charged particles from the sun – the solar wind. “The aurora is a visual warning that electrical currents in space can create these geomagnetically induced currents on Earth.”

The auroral display on May 10 was particularly intense. The auroral appears as an oval around the polar regions, but on that day the arrival of several coronal mass ejections caused the oval to expand. “The auroral region can expand greatly during severe geomagnetic storms,” ​​Oliveira said. “Usually, its southernmost limit is around 70 degrees latitude, but during extreme events it can drop to 40 degrees or even further, which was certainly the case with the storm in May 2024 – the most severe storm in the last two decades.”

I wish you clear skies and big eyes.

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