Eclipse Excerpt 2 of 6

In anticipation of Monday’s total eclipse, this week we’ve got a series of excerpts from the Svalbard chapter of Out in the Cold, in which we traveled up to 800 miles from the North Pole in search of totality in March, 2015. Get a copy of the whole book for yourself, or order the unabridged audiobook.

MYTH

A great chariot carried the sun across the ancient Norse sky, and two wolves gave chase. Suppose they caught it? Some said that was when an eclipse occurred. In old French and German there are expressions like “God protect the moon from wolves.”

To Transylvanians, human failing caused the sun to shudder and turn away in disgust, covering herself with darkness. Putrid fogs gathered, poisonous dew fell from the sky and ghosts swarmed the earth. After an eclipse water and produce were thought contaminated and unsafe, even for livestock. The poisonous dew might bring plague.

Native Alaskans too believed eclipses sent something vile descending to earth. Whatever it was could cause sickness if it settled on cooking tools so women turned over their pots and hid the spoons underneath.

Into the nineteenth century humans would huddle indoors. If they had to go out they would cover their mouths and noses. All across the Carpathian mountains the more superstitious would even destroy clothing they’d left drying outdoors.

In the Faroe Islands 1954 eclipse “a woman named Erla Kirstin Viberg recalled her mother telling her to bring in the sheets from the clothesline so that they wouldn’t burn. ‘People were talking about total destruction,’” wrote Lavinia Greenlaw in The New Yorker.

Since they were accustomed to the sun disappearing for long stretches during the winter, it’s hard to say just how alarmed northern people became at the loss of the sun, but elsewhere people clanged and pounded on pots and pans, screamed, shouted and cried out to scare away whatever evil spirit had descended. The Chippewa shot fiery arrows into the sky hoping to rekindle the sun.

And whoever they were and whatever they did, in time the people were always successful. The demon always left the sun.

•••••

An often quoted statistic by laymen like we in Longyearbyen is the wonder-filled fact that total eclipses are possible only because the sun’s diameter is about 400 times that of the moon, while the moon is about 400 times closer to earth, allowing for the moon’s disk to just cover the sun’s. Consider the serendipity.

Further, we just happen to be here at the right moment in the cosmos.  The moon’s orbit drifts about four centimeters a year away from earth. Scientists have measured its retreat using tools left on the moon by the Apollo program. A billion years ago all eclipses entirely blotted out the sun, and in just fifty million years the moon will be too small when viewed from Earth to ever cover the sun. Even now it barely does. If the moon’s diameter were just 169 miles smaller total eclipses would be impossible.

•••••

Suppose that next Tuesday you wake up on the equator. Swinging in a hammock on the beach and turning with the earth, you will travel 24,901 miles that day, not counting the swinging.

Pull your calculator from your bathing suit, divide 24,901 by the length of a day, 23 hours, 56 minutes and four seconds, and you find that you and your hammock have been traveling 1,040 miles per hour.

Up here, more than the beachwear is different. At Longyearbyen the Earth’s circumference is just 5,101 miles. At 78 degrees north the Earth turns at a leisurely 215 miles per hour. The Central European time zone at Svalbard stretches just 212 miles. With the fastest car and a good road you could just about drive across the time zone before an hour was up and go back in time.

•••••

A legendary Welsh shepherd named Guto Nyth Bran was so fast that he could blow out a candle and be tucked into bed before the light faded. Like the shadow of the moon, he traveled faster than the fastest commercial jet. Except the Concorde.

The speed of the moon’s umbral shadow – the thing that causes totality – varies with the latitude at which it crosses Earth. It can move as slowly as 1,710 kilometers per hour, and Concorde’s maximum cruising speed was 2,200 kilometers per hour, which got scientists thinking. In 1973 a team aboard Corcorde flight 001 chased the moon’s shadow for an incredible 74 minutes of totality across Africa, besting by nearly ten times the maximum earthbound length of totality, which is about 7-1/2 minutes.

The Concorde didn’t go into passenger service until 1976, but in 1973 was in in-flight testing. Packed with gear from a British team headed by Dr. John Beckman with the Astrophysics Group at Queen Mary College, London, flight number 001 rose into the air for a rendezvous.

The pilot, André Turcat, and a crew of four were joined by seven astronomers, two assistants and a photographer for a mach 2.05, hour and fourteen minute totality like no other.

•••••

At the beginning of each lunar month we call the moon “new.” The sun, moon and Earth line up like you did in grade school, one behind the other. Out in space this happens every 29.5 days. Here on Earth the Gregorian calendar rules the business and legal world but the rhythm of the moon regulates more soulful realms like the Chinese and Vietnamese New Years, the Hindu Diwali festival, and the Islamic holy month of Ramadan.

At new moon the moon is between the Earth and the sun, so the sun shines on the side of the moon facing away from the Earth, and the moon is invisible to us, beginning its monthly cycle. The scientific word for this is syzygy, more a word I might connect with human reproduction, or questionable hygiene.

Eclipses occur in clusters. A bit of celestial mechanics shows why. The orbit of the moon is tilted about five degrees from the Earth’s orbit around the sun, so the plane of the moon’s path crosses the Earth’s twice a year on opposite sides of its orbit (called nodes), once ascending and once descending, in intervals of 30 to 37 days. This is when you see eclipses.

(Worthy digression: The moon doesn’t really orbit the Earth. They centrifugally pull each other around a common center of gravity roughly 3000 miles from the Earth’s center).

The orbits of the sun, Earth and moon don’t all sync up, so the sun crosses one of the moon’s nodes and returns to it every 346.62 days, not quite a year. As a result eclipse “seasons” march slightly backward across our Gregorian calendar, as does Ramadan, calculated by the 354 day lunar calendar.

Either the Chaldeans of Babylon were incredibly smart people, or there wasn’t much to do in Mesopotamia hundreds of years BCE. Studying the heavens, the Chaldeans determined that every 6,585.3 days the yearly cycle of the moon around the Earth around the sun repeats, and so every eighteen years ten days and eight hours (or 18 years 11 days eight hours, depending on some dense math about leap years) there occurs a very similar eclipse.

This discovery led to eclipses being grouped into families, each called a saros. Today there are 40 different saros series in progress. Our Svalbard eclipse belongs to saros 120.

For any two eclipses separated by one saros, the moon is nearly at the same position with respect to its node (that point at which the moon’s orbit crosses Earth’s orbit) and is also at almost the same distance from Earth. Not only that, the eclipse occurs at virtually the same time of year.

Saros series are not equal to a whole number of days (eighteen years ten days and eight hours). In those eight hours the earth rotates, so later eclipses are viewed by people a third of the globe away. The path for each successive eclipse in a saros series shifts about 120 degrees westward. Make your reservations for eighteen years from now accordingly.

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