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THE SOLAR ECLIPSE

August 13, 2017

I was driving east on I-26 one morning last week. The rising sun was shining brightly. Suddenly, things became dark. A large eighteen-wheel truck passed me, moving between my vehicle and the glaring light. The big rig momentarily obscured my view of the yellow orb.

This is exactly what happens in a solar eclipse. The moon’s orbit takes it between the earth and the sun, blocking most of the solar rays for a brief time. It is an unusual occurrence; one that most people experience only a few times in their lives.

The total solar eclipse will be best seen in what is known as the totality path. That is the area from which the eclipse will be complete. This seventy-mile-wide path stretches across the United States from Salem, Oregon, to Charleston, South Carolina. Those in the path will be able to see a total solar eclipse on August 21, 2017.  Many in the United States will be able to see a partially blocked sun. Some in the Upstate are directly in the path. Most of us will see only a partial eclipse. The last total solar eclipse visible in the United States was in 1979. The next will be in 2024.

Folks have anticipated this rare cosmic phenomenon. Local schools have even given school children the day off to witness the event. Clare and I are looking forward to having children and grandchildren with us for the spectacle.

A note of caution is important. It is dangerous to look at the sun with unprotected eyes. The intense radiation can damage our retinae. To watch the eclipse, get a pair of special glasses. They can be purchased online. Make sure the glasses are up to the right standard. They should be marked ISO 12312-2. Don’t look at the sun through binoculars, telescopes, or your camera’s viewfinder.

Without getting too scientific, it is helpful to know a little of the vocabulary.

  • Umbra – The center of the moon’s shadow on Earth where a total eclipse is visible.
  • Penumbra – The segment of the moon’s shadow on Earth where a partial eclipse is seen.
  • The chromosphere and corona – During a total eclipse, the moon blocks out the photosphere, the part of the sun we usually see. For those on the totality path, the sun’s corona, or its outer atmosphere, appears like a filmy layer trailing off of the sun’s surface. The chromosphere is the thin red layer encircling the sun.

As you might expect, there have been numerous myths and superstitions connected to solar eclipses.  This cosmic event has caused fear, inspired curiosity, and has been associated with legends throughout history. Even today, an eclipse of the sun is considered a bad omen in many cultures.

Ancient cultures tried to understand why the sun temporarily vanished, albeit briefly, from the sky. Many legends surrounding solar eclipses involve mythical figures eating the sun.  If you use your imagination you can visualize the sun as a big round cheese pizza being slowly devoured by a hungry creature.

In Vietnam, people believed that a solar eclipse was caused by a giant frog gobbling up the sun. On the other side of the globe, Norse cultures blamed hungry wolves. In ancient China, a celestial dragon was thought to feast on the sun, causing a solar eclipse. In fact, the Chinese word for an eclipse is shih, meaning to eat.

There were similar myths among Native American people. The Pomo tribe, who live in the northwestern United States, tell a story of a bear who took a bite out of the sun. Afterwards the hungry bear went on to sample the moon, causing a lunar eclipse. This story may have been their way of explaining why a solar eclipse happens around two weeks before or after a lunar eclipse.

According to Eskimo folklore, the sun goddess, Malina, walked away after a fight with her brother, the moon god, Anningan. A solar eclipse occurred when Anningan caught up with his sister.

The indigenous people of Benin and Togo used a solar eclipse as a teachable moment. According to their legends, the event meant that the sun and the moon were quarreling. The only way to stop them from harming each other was for people on Earth to resolve all conflicts. Sounds like a good idea!

The ancient Greeks believed that a solar eclipse was a sign of angry gods. It was thought to be the beginning of disasters and destruction.

Fear of solar eclipses still exists today. Some people, especially in third world countries, believe an eclipse is an evil omen that brings death, destruction, and disasters. A common misconception is that a solar eclipse can be a danger to pregnant women and their unborn children. In some cultures, young children and pregnant women are asked to stay indoors during a solar eclipse.

The earliest writings we have indicate that people paid attention to eclipses as far back as 5,000 years ago.

In Ancient China, solar and lunar eclipses were regarded as heavenly signs that foretold the future of the Emperor. It was a tradition in ancient China to bang drums and pots and make loud noise during an eclipse to frighten away the dragon eating the celestial bodies. The Chinese Imperial Emperor, Chung K’ang, learned of an eclipse when he heard much noise in the streets as his subjects tried to drive away the dragon. They were successful, but the Emperor’s two court astronomers were reportedly beheaded for failing to predict the event.

The shift from superstition to science was a slow process that began in the cultures of the Middle East and Western Europe.

Ancient Babylonian clay tablets provide records of eclipses between 518 and 465 BCE. Babylonian astrologers kept careful records of celestial events including the motions of Mercury, Venus, the sun, and the moon on tablets dating from 1700 to 1681 BCE. Later records identified a total solar eclipse on July 31, 1063 BCE that turned day into night. The eclipse of June 15, 763 BCE, was recorded by Assyrian observers in Nineveh. By carefully noting local lunar and solar eclipses, Babylonian astronomers were able to predict lunar eclipses and later, solar eclipses, with a reasonable accuracy.

Around 460 BCE, the Greek historian, Herodotus wrote that Thales, a Greek mathematician, was able to predict the year when a total solar eclipse would occur. Details of how this prediction was made did not survive. The eclipse occurred in either 610 BCE or 585 BCE. Thales is said to have visited Egypt, and from the empirical rules in use there for land surveying, brought back to Greece the ideas of deductive geometry later codified by Euclid.

The Greek astronomer, Ptolemy (150 CE) recorded his observations of eclipses. He developed a sophisticated scheme for predicting both lunar and solar eclipses. Ptolemy knew understood the orbit of the Moon including its nodal points when the moon is closest to the Earth.

So by the Second Century CE, total solar eclipses could be predicted with some reasonable accuracy. For a growing segment of the human population they were no longer messages from hostile gods or supernatural forces, but simply an interesting regularity of the orbits of the moon and Earth about the sun.

Solar eclipses were by all accounts events of wondrous proportions. Today we understand eclipses very well. We know how and why they happen as well as when and where they happen. We have seen eclipses from space. We have even used eclipses to probe the laws of physics and to discover new worlds outside the solar system.

Still, eclipses of the sun hold their ancient magic and are fascinating to watch. Early in the morning of September 1, 2016, NASA’s Solar Dynamics Observatory, or SDO, caught both Earth and the moon crossing in front of the sun, better known as a double eclipse. The High Altitude Observatory of the National Center for Atmospheric Research provides an archive of research-quality images of solar eclipses as far back as 1869.

Birds and insects that are active at night may become disoriented during the eclipse. Bats and owls may fly. It’s likely some critters will go into nighttime mode at what they perceive is the approach of sunset. When sunlight reemerges just a short time later, they may become more confused.

My good friend Rudy Mancke, naturalist in residence at the University of South Carolina, will be listening to learn if cicadas start their nightly chatter during the eclipse.

Here is a trivia question for you. What do Wilt Chamberlain, Kenny Rogers, Usain Bolt, and Kirk Neely all have in common? Well, we all have an August 21 birthday.

I am not sure what it means to have a total eclipse of the sun on my birthday. I don’t think it is anything ominous or foreboding. Our children and grandchildren will celebrate with us. I have ordered special eclipse glasses for young and old. I’ll wonder with Rudy Mancke if the cicadas will crank up their nighttime song. I imagine we’ll have pizza for all. Who knows, we may start a new myth to explain the eclipse. It will be about a grandfather who takes a big bite out of a cheese pizza.

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