“Usually you have to go a little ways out of town to get away from those city lights” to see them, said Ryan Metzger, a meteorologist at the weather service office in Fairbanks, who called the display “impressive.”
Other shots captured across the Final Frontier showed arcing bands of light splayed out across the sky like fluttering, glow-in-the-dark wind chimes.
The lights were courtesy of a solar storm, or an eruption of high-energy particles from the surface of the sun. That burst of electromagnetic radiation hurtled toward Earth, where it reached the threshold of a Level 2 out of 5 “geomagnetic storm.” Earth’s natural magnetic field converts that potentially hazardous energy into harmless visible light.
In the case of Saturday’s episode, the source of the energy wasn’t one prolific burst of energy, but rather a stream of solar wind emanating from a “coronal hole.” That’s a cooler region on the surface of the sun out of which the solar wind pours, sending a swift stream of energetic particles into space.
Some photographers even snagged shots of elusive “corona” formations, not to be confused with the solar corona, or the outer layer of the sun’s atmosphere. The term comes from the Latin word for “crown” and describes whirlpool-like curls of the northern lights that pinch off and, from below, appear like a crown of converging blades of light.
In Fairbanks, the scene was accompanied by rare “light pillars,” or vertical columns of light above the ground.
Light pillars form when extremely cold air causes hexagonal ice crystals to be present near the surface. Light reflects off their lower horizontal faces and toward an observer, causing light to appear as a vertical stripe.
A glimpse of the northern lights was seen as far south as northern Minnesota and Wyoming, while some colors were spotted even from the northern United Kingdom. Meanwhile, the full splendor of the aurora appeared over Scandinavia, with stunning shots coming in from Norway, Sweden and Finland.
In Iceland, the aurora was bright enough to be seen even from the streets of Reykjavik, the nation’s capital.
The Suomi NPP/VIIRS satellite, which stands for Visible Infrared Imaging Radiometer Suite, is able to detect and resolve sources of light, including from the northern lights. The satellite was peering down on Alaska when the sky erupted in color as a 300-mile-wide band of aurora descended from the high Arctic. Meteorologists were able to obtain a view from space as tendrils of plasma writhed their serpentine weave.
The northern lights are most common at the peak of the solar cycle, which falls every 11 years or so. When the cycle is in full gear, the number of sunspots, or bruiselike discolorations on the sun, are at a maximum. These sunspots throb with energy and are typically the origin of the “coronal mass ejections” that bring the aurora to Earth.
At present, we’re in “solar minimum,” during which the sun can be spotless for long stretches of time. That makes such epic displays of the northern lights less common. But as Alaskans found out this weekend, sometimes the sky can surprise.