What are anti-auroras, a rare phenomenon that created the letter “E” in the skies of Alaska

A strange northern lights happened this month in the USA. Scientists explain that “anti-black auroras” are extremely rare.

“It came from the northwest and I thought, ‘Wow! It looks like the letter E’ to me,” he said. Todd Saladwho calls himself “aurora hunter” when .

It referred to the phenomenon that was observed in the sky over Alaska, in the USA, on November 22nd. “In a few minutes, he flew over the sky backwards and It looked like a creature with its legs in the air.”

As the name implies, anti-auroras are essentially the opposite of an aurora – they stop gases from emitting energy in the form of light. The result is “dark rings, curls, or spots that punctuate bright colors“, he explains to (ESA).

Normally, The swirling light shows occur only sparsely near the poles, where the Earth’s magnetic field is weakest, explains Live Science. But now they are particularly prominent and widespread due to increased solar activity associated with solar maximum, the peak of the sunspot cycle of about 11 years.

“The black dawn is not, in fact, an aurora: it is a lack of auroral activity in a region where electrons are ‘sucked’ from the ionosphere,” he told ESA Göran Marklund, physicist at the Royal Swedish Institute of Technology in Stockholm.

One from 2015 drew on more than a decade of Cluster mission data, and demonstrated that these structures form when auroras deplete plasma, creating “ionospheric cavities” in the upper atmosphere as the magnetosphere shifts from the strain caused by solar storms.

However, for the anti-auroras, which last between 10 and 20 minutes, to appear, the conditions must be correct, which is extremely rare.

Even so, auroral activity is expected to remain high in the coming years — we just have to look up.