They’re often dancing across the sky while many of us are fast asleep. Some of us are lucky enough to catch the Northern Lights. But have you ever wondered why these spectacular light displays happen? It’s actually not as complicated as you may think.
The earth has a natural magnetic field surrounding it. It’s the weakest at the poles. Charged protons and electrons are emitted from the sun… this is the solar wind. These particles will follow the magnetic field until they get to the weakest points at the poles. When the electrons collide with various molecules in the atmosphere, they create those magnificent colors.
Which molecules they collide with and at what height dictates the color. The most prominent color seen in photos recently has been green. That’s a collision with oxygen molecules anywhere from 62 to 120 miles above the surface.
These energized particles head for the earth at speeds of up to 45 million miles per hour before they collide with our atmosphere. The oldest official citing of the lights was in 2600 BC in China… but Galileo was the first to name them Aurora Borealis in 1619 AD. It wasn’t until the early 1900s that Norwegian scientist Kristian Bireland theorized that these lights were happening from electron collisions. The best places to see the Aurora Borealis is in northern Canada, Greenland, Iceland, Norway, and the coastal waters north of Siberia.
The lights are called Aurora Borealis in the northern hemisphere but they also happen in the southern hemisphere. They’re the Southern Lights, also known as Aurora Australis.