Before the eyes of a stargazer, a blood-red aurora turns into the letter "STEVE."

The weird occurrence has not yet been explained by scientific research.

 

The term "strong thermal velocity enhancement," or STEVE for short, refers to an anomaly in the atmosphere originally recorded in 2018. At the time, amateur aurora chasers in northern Canada reported seeing a thin stream of hazy purple light across the sky. Scientists who investigated the event quickly determined that it was not an aurora, the multicolored glow that arises at high latitudes in Earth's atmosphere when solar particles hit atoms at a high altitude. STEVE was not an aurora. Instead, STEVE was its distinct phenomenon that science could not even begin to explain because it is "totally unknown."

 

Unlike the northern lights, which tend to shimmer in broad bands of green, blue, or reddish light depending on their altitude, STEVE typically appears as a single ribbon of bluish-white light that stabs straight upward for hundreds of miles. This occurs in contrast to the northern lights, which tend to shimmer in broad bands of green, blue, or reddish light depending on their altitude. It is sometimes accompanied by a broken green line of lights that has been given the moniker of the "picket fence" phenomenon. STEVE and its friend with the picket fence can be seen far lower in the sky than a conventional aurora. They can be found in a region of the atmosphere known as the sub auroral region, an area where charged solar particles are not likely to enter.

 

For the first time, a new study just published in the journal Geophysical Research Letters has shown a connection between STEVE and another subauroral structure known as stable auroral red (SAR) arcs.

 

The authors of the new research analyzed the film captured by the New Zealand skywatcher in March 2015 and compared it with contemporaneous satellite views and data obtained from an all-sky imager located at the University of Canterbury Mount John Observatory, which is located nearby. The researchers were able to fully understand STEVE's unanticipated presence on that night by combining these three sources.

 

That evening's sky spectacle started with the apparition of a blood-red SAR arc that swooped at least 185 miles (300 kilometers) over Dunedin, New Zealand. According to data collected by satellites, the arc formation was contemporary with a powerful geomagnetic storm, defined as the precipitation of charged solar particles into Earth's upper atmosphere, lasting for about half an hour.

 

The crimson arc gave way to the trademark mauve streak of STEVE as the storm gradually faded. This signature mauve streak of STEVE slashed through the sky is virtually the same location. Just as STEVE was about to disappear, the structure of the green picket fence shimmered into view. According to the experts' findings, this is the first time that all three structures have been observed forming in the sky simultaneously, one after the other. If true, this could provide fresh insights into the origin and development of STEVE.

 

The researchers wrote in the new study, "These phenomena are distinct from auroras in that their optical signatures appear to be triggered by extreme thermal and kinetic energy in the Earth's atmosphere." Unlike auroras, which are produced by energetic particles raining down into our atmosphere, "these phenomena appear to be triggered by extreme thermal and kinetic energy in Earth's atmosphere."

 

According to observations made by satellites of the event, a geomagnetic storm may have been a significant contributing factor in the parade of skylights.

 

According to what the researchers wrote, during the storm, there was the appearance of a fast-moving jet of charged particles emerged alongside the red SAR arc. During geomagnetic storms, these streams of hot, fast particles frequently arise in the sub auroral zone of the sky. This phenomenon is referred to as sub auroral ion drift or SAID. The satellite data also revealed that the intensity of the stream's heat and speed increased approximately thirty minutes after Steve made his appearance.

 

The researchers believe that a "plausible generation mechanism" for STEVE could be the interaction between these rapidly moving ion streams and nitrogen molecules in the sub auroral zone. When charged, hot particles bash against nitrogen molecules, and the molecules become excited and emit mauve light to burn off their excess energy.

 

The new research sheds light on certain aspects of the unexplained phenomenon, but additional observations of STEVE are required to pin down this notion further. These observations can come from both amateur and professional researchers.

Article source : https://www.livescience.com/steve-blood-red-arc

Image source  : https://pixabay.com/id/photos/bulan-bulan-purnama-langit-1859616/

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