Rare solar eclipse to darken and enlighten

Solar style: Whatever you do, do not look at the eclipse without protective glasses. © Getty

Today more than seven million Americans are preparing to witness the country’s first solar eclipse in 99 years. But why exactly is the “Great American Eclipse” so exciting?

It’s today! Through this morning and the early afternoon, one of the most fabled celestial events in the solar system will be seen across America: a total solar eclipse. Crowds will gather to watch as the sun disappears in the daytime.

And yet a moment that will unite millions of Americans is really just a cosmic coincidence.

A total solar eclipse occurs when the moon obscures the sun, casting a lunar shadow over the Earth, and blanketing an American summer morning in two minutes of darkness.

The moon travels between the Earth and sun about once a month but its tilted orbit means that it is usually too high or too low in the sky to block out the sun. However, about once every 18 months, everything lines up directly, creating the conditions for a solar eclipse.

As the sun happens to be both 400 times wider and 400 times further away than the moon, they appear the same size in the sky. This means that, at a solar eclipse, the sun’s corona is visible around a dark-looking moon.

In 2017 the eclipse’s path takes it from coast to coast, starting in Oregon and going in an arc all the way to South Carolina. An estimated 12m people live in its path, a swath of land 70 miles across.

Even though we know exactly why an eclipse happens, it still has the power to enchant and inspire us. But for ancient cultures, a solar eclipse was more astonishing, as they could not predict it, and it was therefore more frightening. Legend has it that a Chinese emperor executed his astronomers for failing to foresee it.

The Vikings believed that the sun was being “eaten” during the eclipse. Their legend involves two wolves, Hati and Skoll, who sought to eat celestial bodies. The Vikings would make loud noises to scare the wolves away.

This ignorance is still seen in animals. Some animals have reportedly changed their behaviour during an eclipse. Owls may begin to hoot and bats may emerge.

Given that most humans are not going to be fooled by an eclipse again, why are Americans still so excited to watch it happen?

Night and day

“It is an amazing scientific event,” say rationally-minded people. The coincidental nature of eclipses, and the fact that we can predict them hundreds of years in advance, is what makes them so thrilling. Plus, many scientific breakthroughs have been made as the result of eclipses. This is science at its most beautiful.

“It’s about more than that,” reply others. Two minutes of darkness in the middle of the day make us reflect on the awesome power of space. It encourages us to consider the sun and the moon as more than just objects in the sky. It reminds us why ancient people worshipped them, and makes us think about on our own place in the universe.

You Decide

  1. Do you view the solar eclipse as a spiritual or a scientific event?
  2. Why do you think we find space so fascinating?

Activities

  1. Draw a diagram illustrating how a solar eclipse takes place.
  2. Come up with your own imaginary myth to explain a solar eclipse.

Some People Say...

“Inner space is so much more interesting, because outer space is so empty.”

Theodore Sturgeon

What do you think?

Q & A

What do we know?
A total solar eclipse is going to be seen across America today. It will hit land at 9:48 Pacific Coast Time before hitting the Atlantic Ocean at 14:48 East Coast Time. It is the first solar eclipse to be seen across America since 1918. We know that, before astronomers worked out why they happen, many ancient cultures ascribed strange and mysterious significance to these rare events.
What do we not know?
Exactly how animals react. Many reports are anecdotal, but some studies have shown animals reacting to the sudden darkness. For example, daytime fish in reefs near the Galapagos Islands swam to shelter during totality while nocturnal fish were more likely to emerge, while spiders began to take down their webs, only to put them back up again once the eclipse had passed.

Word Watch

Eclipse
The other type of eclipse is a lunar eclipse. This occurs when the moon passes directly behind the Earth into its shadow. It only happens when the sun, Earth and moon are almost exactly aligned (this is called syzygy). This means that the moon has no sunlight beaming onto it, so it looks almost red.
Corona
The outermost atmosphere of the sun. It is made of plasma and can only be seen by the naked eye during a solar eclipse. The word means “crown” in Latin.
Path
The amount of time each place in the path is shrouded in complete darkness depends on how close to the centre of the path it is. The town of Carbondale, Illinois, will be treated to the longest eclipse — about two minutes and 41 seconds.
Predict
We know that the next one will take place on July 2nd 2019 over a wide stretch of the South Pacific, before crossing Chile and Argentina. The next US one will be on April 8th 2024.
Scientific breakthroughs
The corona, for example, was first discovered by an eclipse. The German astronomer Johannes Kepler initially mused that the corona surrounded the moon, not the sun.

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