What are Aurora
The Northern Lights, Aurora Borealis (Northern Hemisphere) or Aurora Australis (Southern Hemisphere) are the result of a collision of high energy particles from the sun and atoms high in the atmosphere causing them to become what is known as excited or ionised. When these elements in the atmosphere return back to a normal state a proton is released in the form of light, the Aurora.
Origin of the Aurora
The energy that drives the Aurora is generated by the sun and the constant release of high energy particles causing what is called the solar wind. Just like a normal wind the strength and speed of the solar wind can change, depending on what is occurring on the surface of the sun. Events such as Solar flares can cause a high density of these particles to be directed towards Earth so creating a solar storm with high solar wind speeds. In turn this then increases the energy in the upper atmosphere so causing large Auroral displays.
Colours of the Aurora
Aurora can come in many different colours depending on which chemical elements in the atmosphere are excited when hit buy the solar wind. The different colours seen depend on which element is interacted with, what height they are and what state they are in. If oxygen is involved then the Aurora can be green or red, nitrogen blue or red.
Where can I see the Northern Lights?
The Northern Lights can be seen anywhere in the Northern Hemisphere which is located within the Auroral oval. Forming a ring around the magnetic North Pole the Auroral oval changes in size depending on the activity levels of the Aurora, however for the majority of the time it falls within a band between 65 to 72 degrees latitude. As with any other astronomy based phenomena there are also other factors that can effect it such as weather conditions and light pollution levels.