Lesson 19
Auroras are among the most popular and most beautiful natural occurrences in the world. They are displays of light which are sometimes seen in the high latitudes of the northern and southern parts of the Earth. Auroras seen in the northern part of the Earth are called aurora borealis, while those which occur in the southern part are called aurora australis. They are also called the “northern lights” or “southern lights.”
Since ancient times, auroras have been described by the Inuit people, some Native Americans, and explorers. They are even mentioned in the Bible. Every northern culture has legends about the lights. The lights are often associated with life after death. One Inuit group even thought that auroras were evil things and carried knives to keep them away.
Auroras are higher in the atmosphere than where the most advanced jet plane can fly. The lowest parts are at least 60 kilometers above the Earth, while the uppermost parts extend 900 kilometers up.
Auroras are actually gases in the atmosphere that glow. Charged particles in the atmosphere hit the gas atoms, causing the atoms to give off light. For example, oxygen about 300 kilometers above the Earth gives off red light, while oxygen around 100 kilometers up produces a bright yellow-green light.
Starting out as faint bands, auroras slowly stretch across the sky. Around midnight, these bands become brighter and begin to glow with a greenish color. When the conditions are right, the lights will appear to be dancing in the sky.
Yellowknife in Canada and Fairbanks in Alaska are two of the best places to experience the magical light displays. Both cities are located within the so-called auroral zone, the band forming a circle around the North Pole. Here, auroras can be viewed frequently, and the lights are at their brightest. If you stand somewhere in the auroral zone, you feel as if you can reach up and touch the dancing lights.
The number of tourists from all over the world hoping to see the northern lights is increasing every year. Every year thousands of Japanese make the long journey north to see them.


Lesson 19 オーロラの不思議 科学・自然
オーロラは,世界で最も人気があり最も美しい自然界の出来事の1つである。それは地球の北部と南部の高緯度地域で時折見られる光のショーである。地球の北部で見られるオーロラは北極光(aurora borealis)と呼ばれ,南部で起こるものは南極光(aurora australis)と呼ばれている。それらはまた北極光(northern lights)や南極光(southern lights)とも呼ばれている。