What are auroras?
Auroras are beautiful colored lights that appear in the air. They are only in the north and south. That is why they are also called the northern and southern lights. But they only appear certain times. They're are made by the atmosphere.
How do auroras form?
Solar winds are winds in the atmosphere with highly charged electrons. First, the solar winds come from the Sun. After 40 hours they finally reach the atmosphere. They go through the magnetosphere, an area of highly charged electrical and magnetic fields. This is how solar winds come to have highly charged electrons. The electrons bump into atoms of the atmospheres elements. The color depends on what atom gets bumped and which height they get bumped at.
Colors of auroras
To get the different colors there must be certain circumstances. These are some of them:
COLOR - ATOM - HEIGHT
Green - Oxygen - up to 150 miles
Red - Oxygen - above 150 miles
Blue - Nitrogen - up to 60 miles
Purple - Nitrogen - above 60 miles