The common name for the aurora borealis is the "Northern Lights." This natural light display occurs in polar regions and is caused by the interaction of particles from the sun with the Earth's atmosphere. When solar wind—charged particles from the sun—collides with gases in the Earth’s atmosphere, it produces spectacular colors, predominantly green, but also red and purple hues. The best viewing times typically occur during the winter months in places with dark skies. The auroras are also visible in the Southern Hemisphere, where they are referred to as the aurora australis or Southern Lights.