Aurora Lights are usually green, sometimes red. However, the geomagnetic storm that hit the Earth On Friday night produced a different and rare color: blue.
The Space Weather website, which shared a picture of the rare light seen in Canada and the US on Sunday, reported that blue auroras are most often seen during intense geomagnetic storms, yet this was a relatively minor one.
Auroras occur when electrons and protons of a geomagnetic storm meet oxygen and nitrogen of the atmosphere. Usually, the colors seen in the sky are those produced by oxygen, yet why nitrogen-blue overtopped the hues of oxygen this time is unclear, the website reported.
When electrons and protons in geomagnetic storms meet oxygen at a height of about 60 miles, a yellow light is produced, while a red light is produced at a higher altitude (about 200 miles). Natural nitrogen produces a red violet light, while the blue aurora results from ionic nitrogen.
According to Space Weather, "In Friday's storm, the electrons and protons stroked the ionized molecular nitrogen (N2+) at very high altitudes and produced a blue glow rarely seen during auroral displays."
