Aurora Borealis visible with the naked eye in Snowdonia overlooking Barmouth Estuary

Northern Lights

Parent & Teacher Guidance
Northern Lights

What causes the Northern Lights? 


To understand what causes the Northern Lights, we need to understand what is happening in the sun, and also understand the Earth's magnetic field. The sun is a ball of hydrogen and other gases. It is about 93 million miles, or 150 million kilometres, from Earth.  


In the sun, hydrogen atoms hit each other and create nuclear fusion. Sometimes, charged particles shoot out of the sun and create a solar flash. As a result, the particles travel through space for two days, about 93 million miles, until reaching Earth. 


A magnetic field protects the Earth, but this is less strong at the north and south poles. Thus, some of the electrons coming from the sun manage to reach the Earth's atmosphere. In doing this, they collide with the oxygen and nitrogen atoms in the Earth's atmosphere. These atoms are agitated, and release energy in the form of light. 


The Lightning looks like sheets or waves, because they follow the lines of force in the Earth's magnetic field. Different gases give the different colours. 

  • Oxygen – gives green light, the most common colour; 
  • Nitrogen – gives a blue, red or purple light. 

The best places to see the Northern Lights are: 


  • Alaska or northern Canada; 
  • Scandinavia; 
  • The north of Scotland, sometimes down to the north of England. They are seen in north and mid Wales if conditions are right. 
  • The Northern Lights can be seen all the way down to the equator, but that is quite unusual. 
  • You have to go a long way from major cities or towns, or light pollution will be a problem. Therefore, remote places are best. 


The Northern Lights are at their best during the winter and also during the months of September, October, March and April. A clear, cloudless night is needed to see the lights. If the moon is full, it is more difficult to see the aurora. 

Similar lights – known as Aurora Australis – can be seen in the Antarctic.

A place far from a populated area.
The Antarctic is the southernmost continent and site of the South Pole and is surrounded by the Southern Ocean.
Northern Lights
The Northen Lights or Aurora Borealis is a natural light display in the Earth's sky.
Magnetic field
The area around a magnet in which there is magnetic force.
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