Unfortunately, Steve is no longer a Northern Lights

The aurora borealis phenomenon happens only in regions near the poles, which become tourist destinations for a multitude of people annually. Although their origin is known, only in 2016 did an amateur astronomer realize that some manifestations had a different coloration and specifically named them Steve, an acronym for Strong Thermal Emission Velocity Enhancement. We talked about Steve here at Mega, when he was recognized as a kind of northern lights, but now it looks like the game has turned.

Steve the unknown

The news may seem like the end of Steve, but perhaps the further development of the research is even more interesting, for instead of dawn it gives evidence that it is a whole new celestial phenomenon. Despite being widely known to photographers for decades, bands with a glow close to purple only caught scientists' attention in 2016.

As much as green was not the predominant coloration, this would be a new type of aurora, but doubts about the origin of the differentiated color remained. A good question always catches the eye of a willing researcher, so a new team has looked into the matter, reviewing records from a Steve who took place in March 2008.

Aurora, only not

Generated by the interaction of solar winds with charged particles of our magnetosphere, usually protons and electrons, the color dance happens by moving these elements through the ionosphere. The displayed tones are usually green, with variations in blue or red, but always producing intense radio signals.

The event was analyzed by the team of physicist Bea Gallardo-Lacourt of the University of Calgary, Canada. They sought to confirm that during a Steve particles fell into the ionosphere just as in an aurora. For this, they used camera images that record the phenomenon and information obtained by the NOOA meteorological satellite - which, besides having the ability to measure the amount of charged particles in the atmosphere, was mapping the area at the moment the event occurred.

What decreed the end of Steve as dawn was the non-detection of these particles, turning the phenomenon into something still unknown, because the purple lights are produced in a different way than conventional auroras.

One possibility is that Steve stems from a flow of high-speed ions and overheated electrons in the ionosfer; yet, it may be formed at a higher altitude. Further testing will be done to verify these assumptions and confirm the true origin of the colors.

For now, scientists are calling the new phenomenon “ skyglow ” - something like glow in the sky, but for us it will always be the fascinating Steve.

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