How the Aurora Borealis Works
The auroras also known as the northern and southern lights are some of the most spectacular skywatching experiences on the planet and never fail to delight observers lucky enough to see them. Auroras can be green, red or blue and often they will be a combination of colors.
The Vikings thought that auroras were reflections off the armor of the mythical Valkyries. To the native Eskimos of Greenland and nearby Canada, auroras were communications from the dead. To American Indians, they were lights from huge campfires far to the north. In medieval times, auroras were omens of war or disasters, such as plague.
Today, we know that they’re a light phenomenon caused by high-energy particles from the sun’s solar winds interacting with the Earth’s magnetic field. Because auroras are caused by the interaction of solar winds with the Earth’s magnetic field, you can see them most often near the poles, both north and south. In the north, they’re called aurora borealis, or Northern Lights. Aurora is the name of the Roman goddess of the dawn, and "boreal" means "north" in Latin. In the southern hemisphere, auroras are called aurora australis (Latin for "south"). 
See how they work in this short video that illuminates the cosmic secret of the Northern lights, one of our planet’s most magnificent wonders: 
Infographic: How the Aurora Borealis Works: 
Here is a stunning photo of the aurora borealis floating over a volcano: 
And here are some stunning impressions of the aurora from northern Norway and Russia: