You would have come across photos and videos or have been lucky to experience dazzling colorful lights in the sky. These beautiful lights are called Aurora australis when seen in the Southern Hemisphere and Aurora borealis when seen in the Northern Hemisphere. They are also called polar lights as they are seen near the Earth's magnetic poles. These are commonly seen in Norway, Finland, Canada, Sweden, Greenland, and Artic and Antarctic circles.
How are they formed?
Our sun releases charged particles(electrons and protons) which collide with the gases present in the Earth's upper atmosphere. This bombardment produces flashes of different colors. As these flashes occur in millions of numbers they appear as dancing. Our planet's magnetic field diverts the charged particles toward the poles.
Photo credit-spaceplace.nasa.gov
The magnetic field of Earth protects us from the intense solar winds. As the solar winds increases, these auroras become more intense. Additionally, the magnetic field lines occasionally recombine on the side of Earth facing away from the Sun due to the solar wind. The Earth's poles get a huge quantity of energy when they rebound like an elastic band. A process known as magnetic reconnection causes breathtaking aurora displays.
The colors of auroras-
The colors of lights are determined by certain factors. Such as:
Altitude
Composition of gases
Density of atmosphere
Level of energy involved
Colors that can be seen in auroras are:
Pink and red- This is produced at 100 kilometers and the particles collide with nitrogen gas at the lower edge.
Green- It is the most common color seen and occurs at 100-300 kilometers when the charged particles collide with oxygen gas.
Blue and purple- These colors are difficult to be seen for the eyes. They form when helium and hydrogen gas are involved.
Photo credit-www.nasa.gov
The International Space Station(ISS) is at the same altitude as the polar lights and therefore the astronauts can observe the lights at eye level.Auroras were seen in India-
Auroras were observed in India for the first time by the Indian Astronomical Observatory which is above Mount Saraswati. This rare phenomenon was captured by a 360 degree camera. The coronal mass ejection collided with the Earth's magnetic field at a speed of 21,60,000 kilometers per hour. As these lights are seen at the poles it was very surprising for India to experience it. It also excited a lot of astrophysicists and researchers.
Photo credit-twitter.com/IIABengaluru
Mythology and Auroras-
The Auroras have been mentioned in many mythological scriptures. Various regions and communities had a variety of beliefs. A few of them are:
Norse mythology- The Vikings worship Odin, the chief God. He took warriors who died in the battle to Valhalla where he lived. The female warriors who are called the Valkyries had spears and shields and they were given the task of leading Odin and the warriors. The Vikings believed that these lights were the reflections of Valkyrie's shield and spears. Some also believed these were the souls of warriors leaving Earth.
The Hudson Bay, Canada- Ancient people of Hudson Bay believed that these Northern lights were the lanterns of the devil which were chasing the lost soul
Sami(Finno-Ugric people)- Sami people believed that these lights were not a sign of bravery but rather the souls of dead people. Observing these lights was a bad omen for them.
The people of Greenland believed that these lights were the dancing souls of children who died during childbirth.
Cree Indians- They thought the lights to be a way to communicate with their ancestors.
These have also been seen on other planets such as Jupiter, Saturn, Neptune, and Uranus. The Auroras is a magical moment to be experienced at least once in a lifetime.
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