What are they?
Aurora Borealis, also known as northern lights have been occurring since the dawn of time. They are always there, even when it is too bright for us to see them. But what are they?
How they appear
Northern lights are caused by charged particles from the sun interacting with Earth's upper atmosphere at a very high speed.
- Charged particles
- Earth's upper atmosphere
- High speed
A more in-depth explanation
The sun is continually pushing out electrically charged particles that travel at 300 and 500 km per second in every direction. Some of these particles leak through the Earth’s magnetic field and are funnelled towards the Earth’s magnetic North and South poles. When the particles from the sun interact with the atoms and molecules high up in the atmosphere, they become exhilarated. Which creates aurora ovals (glowing rings of auroral emission) around the North and South magnetic poles.
- Electrically charged particles from the sun
- Earth’s magnetic field
- Aurora ovals
Why different colours?
The Earth’s atmosphere consists of different atoms like nitrogen and oxygen. These atoms are what causes the colours we can see in the Northern lights. The atoms become exhilarated at different levels in the atmosphere. Green is the most common colour, whereas purple and red are more rare.
- Different atoms in the atmosphere
- Red and purple
Where can they be seen?
Your best chance of seeing the northern lights is by being either under or close to the aurora ovals. The further north you travel, the more likely you are to see them. Some of the best places to see the northern lights are Svalbard and northern Norway.
- Aurora ovals
- Northern Norway