Have you ever looked at photographs of the evening sky filled with green, pink, and purple light, and asked yourself what could be causing that? That is the aurora borealis, or "northern lights," a source of myths and legends for centuries. However, it all has to do with our star, the Sun. The Sun is constantly sending small chunks of itself out into space. This is known as the solar wind, and consists of a large number of protons and electrons. Millions of miles later, the solar wind collides with Earth's magnetic field. Thank goodness, this field acts as a shield and protects the Earth's atmosphere by sending most of this solar wind away. Yet, the magnetic field becomes weaker around the Northern and Southern poles. This allows some of this solar wind to get through, following along the magnetic field lines before entering the top of the atmosphere. There, it collides with gas molecules in the atmosphere, like those of oxygen and nitrogen. This collision adds energy to the gas, and that energy is emitted in the form of light. Like in a neon sign, the specific gas that you are hitting determines the color. Oxygen higher in the atmosphere is more likely to produce red light, while lower down, it creates the greenish hue seen the most often. Nitrogen usually produces blues and purples. So essentially, the sun, ninety three million miles away, is turning our atmosphere into a light bulb.

The aurora borealis is visible in high latitudes in the Northern hemisphere, or high latitudes in the Southern Hemisphere, and it is most prevalent when the night is clear. If you happen to be in the Northern Hemisphere, these are some of the best spots to see the lights:

Alaska
Northern Canada
Iceland
Scandinavia
Russia

The time of year to see this is from late August to early April because the nights are long and dark. As for the weather, you need the night sky to be completely clear, because clouds will cover the view no matter the magnitude of the aurora borealis. In addition, it is best to view it near the equinoxes in September and March because that is when the solar wind usually hits the Earth's atmosphere. It is also worth mentioning the solar cycle. The sun has an 11-year cycle in which its activity ebbs and waxes. As the solar cycle approaches its maximum, the solar maximum, there will be more sunspots and solar flares. This will produce more frequent and intense aurora activity. It seems we are quickly approaching this maximum in the coming years, making now the perfect time for a trip to see this amazing phenomenon.

In the end, the aurora borealis is a beautiful reminder that the Earth is interacting with the sun. The solar wind and Earth's magnetism are like a cosmic waltz, with the Earth's atmosphere acting as the stage upon which the show happens. Next time you see that green aurora, think about the solar wind greeting the upper atmosphere. Pretty cool, if you ask me.