Natural Phenomenon / 7 min read / 11 August 2021
Most people have probably heard of an aurora, also referred to as polar lights,
northern lights (aurora borealis) or southern lights (aurora australis), a
magnificent display of natural light seen in the Earth’s sky. Aurorae can
usually be experienced in high-latitude regions, predominantly around the
Arctic and the Antarctic.
Originally derived from the name of Roman goddess of the dawn Aurora, the northern lights feature in several myths and legends, most prominently in Norse mythology where the lights were suggested to be glow from the shields and armors of the female warriors Valkyrie. Others such as the Cree Indians of North America believed it to be the spirits of the dead, trying to communicate with their loved ones on earth.
But what exactly causes this famous light phenomenon ?
The aurorae are caused by the Sun. Apart from heat and light, the Sun sends several things towards us, like energy and small particles. The Earth’s magnetic field shields us from most of these. Sun also streams solar winds and solar storms which contains charged particles. If the Earth is in the path of a stream, our planet’s magnetic field and atmosphere react. Earth’s magnetic field tries to deflect it, however some charged particles reach the atmosphere and strike the atoms and molecules, causing them to get excited. The excited electrons move to higher-energy orbits further from the nucleus. When they come back to lower-energy orbits, they release light.
Oxygen atoms cause green and red whereas Nitrogen emits purplish blue which is a rare color to see. Although an aurora often appears as curtains of light, they can also be arcs or spirals, following lines of force in Earth’s magnetic field. They have also been observed on other planets of Solar System, exoplanets, comets and other extra-solar bodies.
The best places to witness the Northern Lights ( from Earth of course) are from Norway, Sweden, Finland, Iceland, Canada, Greenland and Alaska.