Also called Polar Lights
An aurora, also called Polar Lights, is a natural atmospheric phenomenon display in sky. Auroras are an effect of disturbances in the magnetosphere caused by electrically charged particles from Sun wind interact with gases present in the Earth's atmosphere.
The colours of the Auroras vary from region to region, from place to place - green, yellow, purple and red are common colours. Green is most common colour among all.
Aurora Borealis: Also known as Northern Lights, is the aurora display that occur in Northern hemisphere of the Earth.
Aurora Australis: Also known as Southern Lights, is the aurora display that occur in Southern hemisphere of the Earth.
Why does auroras have different colours?
It mainly depends on the gases that are present in the atmosphere. For example, oxygen emits green and red light. But nitrogen glows blue and purple.