Aurora Borealis, also known as the Northern Lights, as well as its southern counterpart, Aurora Australis, is truly an entrancing and magical experience. Its display has captivated human beings throughout the centuries. It is the outcome of an incredible journey, which starts at the heart of our Solar System – the Sun. The core of our star can reach an unimaginable 15 million C, transforming its surface into a boiling mass of hot plasma. It is crisscrossed by numerous magnetic lines, which upon colliding form sunspots. There particles of plasma, called solar wind, are hurled into space and some eventually make it to the Earth. Most of them are deflected by our planet’s magnetic field, but a small portion do manage to get through around the North and South Pole. Upon entering the atmosphere, they collide with different gas particles, transferring some of their energy. In order for these excited gas particles to return to normal, they give off that energy in the form of photons. Based on the different gas elements, their structure and altitude, this light is emitted at different wavelengths, which is the reason for the many beautiful colors that we see. Oxygen emits either a yellow or green light, while nitrogen tends to be red, violet or even blue. The latter is caused by atomic nitrogen, as molecular is more purple. Different combinations of these colors can even lead to pink, orange, or white.
In the past the many indigenous people living in the polar areas created their own legends and superstitions, explaining the origin of the mysterious lights in the sky. The Inuit used to play a game, similar to football and believed that the spirits of the dead were kicking the frozen head of a walrus, leaving light in its wake. Native Americans thought it was a path to guide souls to the afterlife. In Europe most tribes believed they were a herald of war and destruction.
The name Aurora Borealis was first used by Galileo Galilei in 1619, after the Roman goddess of the dawn Aurora and Boreas, meaning “north wind” in Greek. The oldest written record dates back even further, to Ancient Babylon. The official astronomer of King Nebuchadnezzar II wrote on March 12, 567 BC about an unusual red glow in the sky. But the earliest depiction are some 30,000-year-old cave paintings in France, illustrating the natural phenomenon.