Northern Lights: Here is everything kids need to know

The Aurora Borealis or the Northern Lights, an astronomical phenomenon, are seen shimmering across the sky in the form of curtains or shafts of coloured lights. The lights glow in the night sky in unpredictable patterns, often vivid and barely perceptible. Auroras occur due to the interaction between the solar wind and the earth’s magnetic field. Here is a low-down on the Northern Lights. 

What are the Northern Lights? 
The phenomenon occurs when large numbers of electrically charged particles (electrons) of high-speed head towards the surface of the earth along their magnetic field and collide with the highest air particles. This causes the air to light up in the form of a fluorescent tube. Every atom that collides with the particles gains a surplus of energy. When this energy gets released, the lights appear. The resulting colours reflect through the gases found in the atmosphere. The most usual yellow-green colour is because of the presence of oxygen. Other colours include red that is emitted due to oxygen and nitrogen. The popular violet and blue colours are seen at the lower edge of the auroral range due to the contribution of nitrogen. 

The charged particles originate from the sun and it is the weather conditions that determine the occurrence of the northern lights across the sky. These particles are continuously emitted from the sun while some are captured by the earth’s magnetic field forming the lights.   

What do scientists have to say? 
The Swedish Institute for Space Physics has decades of scientific research on the Northern Lights. Scientists say that the particles originating from the ionosphere travel at an enormous speed. After the collision, the particles tend to ‘rub off’ exchanging the gained energy and continually moving along to another atom. This process releases the northern lights into the sky to create a mesmerizing scene. 

Where can we see the Northern Lights? 
As the name suggest, they are found in the polar regions. Northern Lights occur most frequently in a belt of radius 2500 km centered on the magnetic north pole. The auroral zone extends over northern Scandinavian Island, the southern tip of Greenland over to Canada, Alaska, and along the coast of Siberia. The Northern Lights can be seen from both the north and south regions. There exists an auroral zone in the southern part, called the Southern Lights which stretches over Antarctica and the surrounding ocean. The Northern and Southern Lights occur simultaneously and are mirror images of each other.  

What do Northern Lights look like? 
The Aurora Borealis can appear in various shapes including arches, bands, and coronas. Early at night, the lights usually strike in a long arc shape stretching across the sky from east to west displaying fuzzy green shades. The curtains of lights sometimes appear in the sky moving in the same direction as the magnetic fields of the earth. The length of one arc can reach up to 1000km while the width remains limited to 100m. The corona shape appears when you stand just below the direction of the magnetic fields. Scientists say there is always a Northern Light present in the sky. It is only the direction that determines its appearance from ground level.