Strange patches of glowing light have been spotted drifting across Europa’s night sky after a solar storm, puzzling onlookers.
The strange sight happened on April 23 when a coronal mass ejection (CME) from the sun crashed into Earth’s atmosphere, causing a “severe” G4 geomagnetic storm.
Sky watchers were prepared to observe the auroras, which typically occur during a CME-triggered geomagnetic storm, but as some in Europe watched, the aurora began to change into unusual patches.
“I had never seen anything like this,” Heiko Ulbricht of Saxony, Germany, told SpaceWeather.com. “The auroras began to tear apart, pulsating as they formed separate patches that floated high in the sky.
“It literally took my breath away,” he said. “My pulse was still racing hours later.”
Uploaded by social media users Ulbricht’s pictureamazed at the sight.
These were actually proton auroras caused by Earth’s invisible planetary rings made of electricity called ring currents. They consist of electrically charged ions that flow around the Earth in a massive ring of electric current.
During particularly strong geomagnetic storms caused by the jet of solar plasma from a CME hitting the Earth’s magnetic field and atmosphere, protons from this ring system can shower onto our planet. This causes a secondary shower of electrons that react with gases in our atmosphere, causing these strange auroras.
Brett Carter, associate professor of space science at Australia’s RMIT University, said earlier Newsweek: “The different colors result from the release of electrons from different energy levels from oxygen – the most common reds and greens – and nitrogen – dark reds/blues.”
Unlike normal auroras, which are triggered by CME particles and particles from Earth’s magnetosphere hitting the atmosphere, these proton auroras are caused by Earth’s invisible rings. Proton auroras also tend to pulsate due to plasma wave activity in Earth’s ring current. They appear more often during sunset, as Earth’s magnetosphere pushes protons toward the twilight side of the planet.
However, the exact reason for the auroras breaking in such a strange way is not yet known.
“We still don’t know why the proton auroras seem to break up in such a dramatic way,” space physicist Toshi Nishimura of Boston University told SpaceWeather.com. “That’s a question for future research.”
These proton auroras were also observed over France, Denmark and Poland.
During the same geomagnetic storm, the normal auroras were seen further south than usual due to the strength of the storm. Photos on social media captured the northern lights as far south as California, as well as Illinois, Wyoming and Nevada.
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