Double Aurora Cut By Amateur Could Solve Mystery Behind Rare Phenomenon

A double red-green aurora borealis lights up the sky over Canada.

A double red-green aurora borealis lights up the sky over Canada. Image Courtesy of © 2021 ALAN DYER/AMAZINGSKY.COM

Looking out of his backyard in the Canadian city of Strathmore, amateur astronomer and photographer Alan Dyer saw an unknown sight dancing in the night sky: rippling arches of reddish pink aurora borealis underlined with another band of aurora in the classic green color. Later it became clear that the same phenomenon had also been recorded in the Finnish cities of Ikaalinen and Orimattila.

Not only did the scene yield some stunning images, the strange observation is now helping to unravel the mystery of how double red and green auroras are formed. Together with satellite observations, Dyer’s photos and the other images seem to show that the two phenomena may be closely related.

In a paper published in the Journal of Geophysical Research: Space Physicsphysicists found that the green proton aurora transitioned into the stable auroral-red (SAR) arc, and this was initiated by proton precipitationwhich had been suggested but never successfully demonstrated before.

It is known how greenish yellow aurorae are being formed. They are the product of solar wind, charged particles emitted by the sun and flowing toward Earth. When these energetic electrons and protons collide in Earth’s magnetosphere, they release energy and excite gases in our upper atmosphere. The excitement causes ionization of the atmospheric molecules and the release of light photons. Different elements can produce different colors.

However, the formation of stable aurora red arcs is less clear. The researchers claim that red auroras are different from another recently discovered aurora called STEVE because they lack the purple-mauve hues, as well as other defining features.

However, citizen scientists — who have contributed significantly to our understanding of auroras in recent years — have recently documented a red arc. evolve into a STEVE For the first time.

In the new study, Dyer and an international team of physicists and other citizen scientists suggest that the pink-red band may be caused by electrons.

According to their observations and the images captured of the phenomenon, the green aurora quickly diffused and faded, but the red arc remained more stable and drifted toward the equator during the substorm’s recovery phase.

Proton showers cause the classic green aurora. The proton aurora then transitions into a stable aurorae red arc as secondary electrons enter the image by raining down through the atmosphere. Red light has lower frequency so it requires less energy to produce hence the red aurora is produced by the electrons which have lower energy as compared to protons. However, both are the product of the same gusts of solar wind blowing in and over the Earth’s upper atmosphere.

This is just one theory, the researchers say, but yet another discovery that shows just how complex the simple beauty of the Northern Lights can really be.

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