Polar Light Shows

Beginning:
The beginning grabs the reader’s interest and leads to the thesis statement (underlined). The first record of the northern lights comes in a 30,000-year-old cave painting in France. From that time to this, people around the world have looked up in hopes of seeing one of these dramatic light shows. Curtains of red and green billow across the sky or whirl overhead. Auroras seem to cast a mystical spell on observers, but science can explain how they come to be.

Middle:
Each middle paragraph deals with a different part of the topic. Auroras start with the solar wind, a constant tide of charged particles thrown off by the sun. At high speeds, electrons crash into earth’s upper atmosphere and accelerate along its magnetic field lines toward the poles. The north and south poles of the earth are just like the north and south poles of a magnet. Electrons follow the field lines down toward the poles, where they energize gas atoms. As the atoms release their extra energy, they glow. Nitrogen glows red, and oxygen glows green—the most common colors in auroras. Neon lights glow from the same process.

Auroras can form at any time of day, but they are visible only in a dark sky. They tend to be best observed around midnight. Most auroras form in an oval around the polar region but then they can spread out, migrating away. Sometimes, auroras appear as far south as the lower 48 states. If the magnetic poles flip (as they have many times in the past), there will be a period when auroras will be visible everywhere.

The writer elaborates with a variety of details. Auroras have mystified people throughout time. In 567 B.C.E., an astronomer of King Nebuchadnezzar II reported seeing the lights. For thousands of years, Viking legends held that auroras are reflections off the armor of the Valkyries, the goddesses who ride chariots through the skies to harvest the souls of warriors from battlefields. An Inuit legend says the lights are spirits playing ball with a walrus’s head. In 1619, Galileo first called these lights aurora after the Roman goddess of the dawn and borealis after the Greek god of the north wind. (Aurora australis means “dawn of the south”—the southern lights.)

A topic sentence begins each middle paragraph. Scientists are still discovering their mysteries. At the beginning of the 20th century, Kristian Birkeland first suggested that auroras come from the solar wind, but his theories were not accepted until the middle of the century. It took until 2021 for scientists to discover how the electrons surfed waves to reach their phenomenal speeds of 45 million miles per hour. The Parker Solar Probe was even sent to learn more about the solar wind by entering the sun’s corona!

Ending:
The ending leaves the reader with a powerful thought. Scientists and regular people may see auroras through different eyes, but all observers feel wonder. The dazzling curtains of light billowing from horizon to horizon should be reason enough. However, auroras are even more wonderful as reminders that our atmosphere is protecting us from the ravages of the solar wind.