There are nights in the far north when the sky seems to be painted with a glowing, colorful brush. The northern lights, also known as the Aurora borealis, are one of the most beautiful sights in Earth’s atmosphere.
Sometimes the sun releases electrically charged particles that travel toward the Earth. Once in our atmosphere, the particles collide with gases in our own air. This happens at least sixty miles above the planet’s surface. The result of each tiny collision is a colorful glow. When millions of these illuminations happen at the same time, the northern lights are visible.
We see the Aurora borealis in many different ways, and they are always spectacular. They might seem like a wall of light or huge swirls across the sky. The light often appears to be moving or rippling. Sometimes it looks like color is raining down. The colors of the display are usually pink or pale green, but other colors show up too. It depends on where the observer is and what kind of gas is involved. If nitrogen particles explode, the light will be blue. Another factor is how high up the particles collided. At around 200 miles above the earth’s surface, the explosions produce red light.
Electrons and protons leave the sun when gas particles bump into each other at incredibly high temperatures. The charged particles get thrown off the surface of the sun at such a high speed that they blow toward Earth. This is known as the solar wind. Scientists believe that every eleven years, there is a peak of this kind of activity. Although northern lights are more common in these periods, they can happen at any time.
The earth has a magnetic field that keeps most of the charged particles out of the atmosphere. At the north pole and south pole, however, the magnetic field is weaker. That is why the sun’s particles tend to get into our atmosphere at the poles. The northern lights are what we see from particles colliding at the north pole. At the south pole, a similar thing happens, which is called the Aurora australis.
To see the northern lights, it certainly helps to be above the Arctic Circle, an area so close to the North pole that the angle of the sun is different from the rest of the world. At the summer solstice in June, the sun shines for 24 hours, whereas at the winter solstice in December, there is no sun at all for 24 hours. Being so close to the pole also means a great view of the northern lights.
For example, in the region of Finland called Lapland, the northern lights are visible nearly 200 nights annually. Norway is another great vantage point for the Aurora borealis. They are more commonly seen above the city of Tromso, Norway, than anywhere else on earth. There are some good spots in Scotland as well as Canada; for viewing in the United States, your best bet is Fairbanks, Alaska. In all these regions, hotels and resorts offer special packages to encourage tourists to come and enjoy the natural light display. Some even provide a wake-up call in the middle of the night so you don’t miss the best opportunity for observation.
Surprisingly, the northern lights can also be seen in Pennsylvania. Although Cherry Springs State Park is a long way from the Arctic Circle, its skies are so dark that you can see the lights glowing from the distant north.
