Rainbow of the night: Researchers are puzzling over an eerie sky phenomenon

It’s an eerie phenomenon observed by an amateur astronomer in New Zealand in March 2015. A band appears in the night sky, iridescent in red-purple tones. Now researchers have analyzed the phenomenon in a new study published in the journal Geophysical Research Letters. Dubbed STEVE by astronomers, the phenomenon is similar to auroras, but the celestial arc is said to be a different phenomenon. In contrast to the green, white, or purple auroras that stretch across the sky, STEVE appears as a red-purple band that relaxes linearly across the night sky. Sometimes a green flicker also appears next to the arc. In their study, the researchers compared three pieces of data on the phenomenon: the recording by the amateur astronomer, satellite images and data of the night sky from New Zealand’s Mount John Observatory. The researchers can use the different data to prove a geomagnetic storm in the region on that night. A strong stream of fast-moving iron particles was measured in this storm. The interaction of these charged particles with nitrogen particles could be responsible for the celestial phenomenon. In their study, they write about the strange arcing: “These phenomena differ from auroras because their optical signatures appear to be triggered by extreme thermal and kinetic energy in Earth’s atmosphere, rather than being produced by energetic particles raining down into our atmosphere.” However the researchers emphasize that further data and evaluations are needed in order to be able to fully explain the rainbow of the night. Her mystery does not detract from the beauty of this apparition.
Source: ScienceAlert