Scientists Crack Mystery of Unknown Glowing Celestial Phenomenon 'STEVE's Source Region in Space
Astronomers come across stunning phenomena in the sky on a regular basis. However, some of them manage to steal the hearts of experts and the public alike. In 2018, a celestial miracle managed to do that and left researchers astounded regarding the reason behind its beauty, stated AGU. Findings regarding this phenomenon have been published in Geophysical Research Letters.
The phenomenon in question is STEVE. In 2018, social media became filled with this beautiful display featuring a thin ribbon of pinkish-red that spreads across from east to west. This interplay of lights was sometimes joined by green vertical columns of light categorized as 'picket fence' by experts. The stunning pattern was labeled as STEVE and later identified to be a kind of sky glow.
Initially, researchers were unsure whether the phenomenon was an aurora because of how far it extended. A 2018 study proved these doubts correct and claimed that these light patterns were distinct from auroras. Auroras come into being due to glowing oxygen and nitrogen atoms present in the planet's upper atmosphere. These atoms get excited due to charged particles arriving from the near-Earth magnetic environment called the magnetosphere. Researchers associated with the 2018 study claimed that STEVE's glow was not because of the charged particles. This made it stand apart from auroras.
The study on Geophysical Research Letters finds out STEVE's origins. The pursuit was not easy at all because STEVE often appeared during solar-induced magnetic storms, making analysis difficult. Experts took into consideration satellite data and several ground images of STEVE, for their examination. The results indicated that the pinkish-red ribbon and the green vertical columns were two different phenomena altogether. Both were due to separate processes.
The picket fence was produced the way typical auroras are created. However, the pinkish-red ribbon was happening because of the charging of particles above the upper atmosphere. "Aurora is defined by particle precipitation, electrons, and protons actually falling into our atmosphere, whereas the STEVE atmospheric glow comes from heating without particle precipitation," said Bea Gallardo-Lacourt, a space physicist at the University of Calgary and co-author of the new study. "The precipitating electrons that cause the green picket fence are thus aurora, though this occurs outside the auroral zone, so it’s indeed unique."
Researchers noted in the examination that whenever STEVE happened, several charged particles in the ionosphere clashed with each other. This heated the particles, leading to the interplay of lights. Incandescent light bulbs also follow a somewhat similar process. The 'picket' portion also has subtle differences from the usual auroras, as in this case, the atoms impact a far south region of the atmosphere, which is not observed in auroras. This made researchers claim that the atoms were getting knocked out of the magnetosphere and falling into the ionosphere to create the striped effect.
Experts were thankful for the on-ground photographs they had of STEVE which helped them in getting accurate findings. "As commercial cameras become more sensitive and increased excitement about the aurora spreads via social media, citizen scientists can act as a ‘mobile sensor network,’ and we are grateful to them for giving us data to analyze," Toshi Nishimura, a space physicist at Boston University and lead author of the new study said.