Maybe you have looked at pictures of the night sky filled with green, pink, or purple light and thought, "What is going on up there?" Well, that light is what we call an aurora borealis (or northern lights), and people have made legends and myths about it for hundreds of years. But it is nothing magical, it is just our sun. The sun is always shooting little bits of it out into space. That stream of particles, mostly protons and electrons, that travel from the sun all the way to Earth is called the solar wind. Those particles fly through space and crash right into Earth's magnetic field. We are saved from those particles because the magnetic field protects us and bounces the solar wind out into space. However, the magnetic field is weaker around the North and South Poles, and some of the solar wind finds it's way in along the magnetic field line, and goes all the way down into our atmosphere. The particles will then hit some of the gases in our upper atmosphere like oxygen and nitrogen. The collisions will excite the gas, which will emit light when they are relaxed. Basically, the gases in our atmosphere are glowing like a neon sign, and the different color comes from different gases. Oxygen gives off a red light when at a higher altitude, but when they are at a lower level they glow green, which is the most common color. While nitrogen gives off a blue or purple light. All of it is caused by the sun, 93 million miles away! You can't really see the Aurora Borealis in most parts of the world, you need to be quite far north or far south to get a good look at it. You don't want to see it near a big city because it is too light and you won't be able to see it well either. The best places to see it in the northern hemisphere are Alaska, Northern Canada, Iceland, Norway, and Russia. You are more likely to see an Aurora in the fall, winter, and early spring months (Late August to April), when the nights are longer and it is darker. Also the sky has to be completely clear! If the clouds come in during the time of the Aurora you won't be able to see it at all. The Aurora Borealis is best to view around the times of the equinoxes, September and March, since the solar wind seems to hit the Earth just right at that time. You also want to keep an eye on the activity of the sun! The sun has an 11 year cycle, and right now is approaching solar maximum, when it is in full swing. At the solar maximum there are the most sunspots and solar flares. The solar flares give out stronger solar wind, which results in more and brighter Auroras. It would definitely be a good idea to travel to a high latitude country in the upcoming years to see an Aurora Borealis. In conclusion, this Aurora Borealis is a cool way to remember that we are part of a larger solar system, and that we are always interacting with the sun. If you ever have a chance to see the Aurora, you should know that this green light shows that the solar wind in the upper atmosphere is saying hello! That's a pretty cool thing isn't it?