If you have ever seen photos of the night sky swirling with green, pink, and purple light, you have probably wondered what is actually going on up there. That beautiful glow is called the aurora borealis, or the northern lights, and it has sparked myths and legends for centuries. But the real cause is not magic or angry gods. It all starts with our sun.

The sun is constantly throwing tiny pieces of itself into space. This stream of charged particles, mostly electrons and protons, is known as the solar wind. It travels millions of miles and eventually slams into Earth’s magnetic field. Fortunately for us, that field acts like a giant shield, deflecting most of the solar wind away. But near the North and South Poles, the magnetic field is weaker. Some of those particles sneak in along the field lines and race down into our upper atmosphere.

Once they get there, they collide with gas molecules like oxygen and nitrogen. Those collisions add energy to the gas molecules, which then release it as light. Think of it like a neon sign. Different gases create different colors. Oxygen at higher altitudes tends to produce red light, but lower down it glows green, which is the most common shade. Nitrogen gives off blues and purples. The whole thing is a massive light show powered by the sun from ninety three million miles away.

So when can you see this happen? You need to be far north or far south, away from city lights. In the northern hemisphere, the best places are Alaska, northern Canada, Iceland, Scandinavia, and Russia. The season runs from late August to early April because you need long, dark nights. The sky has to be clear too. Clouds will ruin the view no matter how active the aurora is. Also, the lights are strongest around the equinoxes in September and March. That is when the solar wind tends to hit Earth at just the right angle.

You also need to pay attention to solar activity. The sun goes through an eleven year cycle, and at its peak, called solar maximum, you get more sunspots and solar flares. That means stronger solar winds and more frequent, brighter auroras. We are heading toward one of those peaks soon, so the next few years are a great time to plan a trip.

In the end, the aurora borealis is a reminder that our planet is not isolated. It is constantly interacting with the sun in a dance of particles and magnetic fields. And if you ever get lucky enough to stand under a rippling curtain of green light, just remember that you are watching the solar wind say hello to the upper atmosphere. That is a pretty cool thought.