The northern lights are hard for most people to spot in person: They mainly occur during the winter in upper reaches of the Northern Hemisphere. An even rarer sight is an anti-aurora or black aurora.
Live Science reports that an aurora hunter named Todd Salat photographed one on November 22 in south-central Alaska at about 4:00 a.m. The sky-gazer said the anti-aurora looked like the letter E and changed shapes, sailing “overhead on its back and (looking) like some critter with its legs in the air.” The light show was over within a few minutes.
What is an anti-aurora, exactly? According to the European Space Agency (ESA), it’s a series of black regions in the aurora borealis. It may appear as dark circles, swirls, or shapeless blobs. This phenomenon results from electrons propelling into space through holes in the ionosphere, the opposite of what happens during a normal aurora, when electrons shoot down from space and collide with particles in the ionosphere to produce colored lights.
Anti-auroras were only discovered in the late 1990s. Moreover, scientists had no idea how they functioned until 2001, when four ESA satellites traveled above a black aurora, sensing small pockets known as positively-charged electric potential structures in the upper atmosphere.
Even then, experts only vaguely understood black auroras. A 2015 study made things clearer: Scientists used over a decade’s worth of ESA satellite data to dissect the mystery behind the structures. They found that they form when auroras loose plasma, which causes “ionospheric cavities” in the upper atmosphere. At the same time, the magnetosphere moves due to pressure caused by solar storms.
These conditions have to be just right for the phenomenon to unfold. While the northern lights can last a few minutes to hours, anti-auroras only appear for about 10 to 20 minutes at a time.
Check out these destinations if you’re looking for affordable places to see the northern lights. Increased solar activity has produced some dazzling light shows in the past year, and scientists say it will likely peak in 2026 or 2027.
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