St. Patrick’s Day was a lucky day for Northern Lights hunters this year with the highest visibility in over decade. And how fitting, too. Chicago has its green river every St. Patty’s Day. Finland, Norway, and everywhere the light touches, regardless of their St. Patrick’s-related reverie, happened to have the green-hued wonders of the Northern Lights.
Imagining the early Northern Lights sightings, it really must have been eerie and reminiscent of extraterrestrial activity. Nowadays, who wouldn’t want a glimpse of this otherworldly beauty? Is it possible for aurora borealis (its scientific name) to get old?
Last night, the majority of the United States got some Northern Lights action. In the Trøndelag region of Norway, collected pictures were taken from both in the morning and night. The currents reached as far down as Germany, and relatively low latitude regions of central Russia.
Photo Courtesy of Gunnar Soreng
Normally, the aurora borealis hovers in regions closer to the Polar Circle. The strength of this solar storm impacting the Earth’s upper atmosphere is abnormal, and one of its magnitude that would normally occur some like every 11 years. Solar wind causes the Northern Lights without a solar storm necessarily concurrently happening. With the storm, the lights are so much brighter. Storms like these are called coronal mass ejections (CME), which is kind of like the Sun’s release of energy. Perhaps the massive solar storm is due to the Sun’s unusual quietness.
When its strength lightens, the glow is a faint green. To be sure the Northern Lights are what you’re seeing, a trick is to use a long exposure (30+ seconds) and check the photographs for pillars of green light reaching up from the horizon. The green—dynamic and continually changing—is from oxygen, the reds from neon, and the purples argon. The color depends on the molecules. They are all high-energy particles heading away from the sun, as the sun toward the Earth’s upper atmosphere. There’s a reason that aurora borealis is technically a “solar storm.” Slate’s science writer and astronomer, Phil Plait wrote a clear explanatory piece, identifying its causes.
For future Northern Lights live-action tracking here’s your tool. You can even see how incredibly quickly its moved upward toward the Arctic Circle as if back to normal strength.