Mysterious 'blue' aurora leaves skywatchers puzzled. But what caused it?
The bluish-green display of lights that was recently observed in the skies over the Lapland region in Sweden was not an ordinary one. On November 3, skywatchers were surprised to see a strange flash of stationary blue light over there. Interestingly, the usual green aurora was moving around it. Experts believe that the test-firing of Russian ballistic missiles could have caused this.
Why does this story matter?
Aurora Borealis is a natural display of lights observed in the night sky. This stunning phenomenon results from the interaction of highly energetic particles from the Sun with the upper layer of Earth's atmosphere. Our planet's magnetic field diverts these particles toward the North Pole. But even meddling by humans can sometimes lead to unexpected instances of natural beauty.
Atmospheric nitrogen is the reason behind blue auroras
The colors of the auroras are determined by the composition of Earth's atmosphere. The commonly seen green auroras are produced by oxygen molecules. Meanwhile, the bluish light in auroras usually depicts the presence of nitrogen. When energetic particles from space interact with ionized molecular nitrogen at high altitudes, an azure glow is produced. This is frequently observed during geomagnetic storms.
A similar blue aurora was observed in 2017
This is not the first time that a blue aurora was observed. A similar phenomenon was observed in the skies above Arctic Circle in October 2017. Coincidentally, around the same time, the Russian military conducted a drill, launching several missiles from land, air, and sea.
Russian ICBMs were responsible for the blue aurora
"Our team of photographers has been photographing the night sky for more than a decade and this event was unlike anything we have ever seen," said Chad Blakley, the director of Lights over Lapland, an aurora tour company. Puzzled by this scenario, he reached out to experts in this field. They concluded that this was due to Russian submarines testing ICBMs (Intercontinental ballistic missiles).
Blue exhaust from ICBMs were carried by high-altitude winds
During the 2017 incident, a 'magnificent cloud of blue exhaust' appeared right after the Russian military test. It is claimed that a Topol ICBM was used. According to spaceweather.com, high-altitude winds could have directed this blue exhaust westward this time too, causing it to join geomagnetic auroras over Scandinavia. Notably, the blue and green lights were moving independently, since they originate from different sources.
