What is a solar eclipse? In simple terms, it’s the shadow of the moon crossing the surface of the earth. It occurs when the earth, sun and moon are aligned. The moon gets between the sun and the earth for a brief period of time and blocks the sun’s light on a portion of the earth.
The fact that we can have such an awe-inspiring phenomenon is actually due to a cosmic coincidence. The moon is 400 times smaller than the sun, but it’s also 400 times closer to us than the sun. So from our perspective, the two celestial bodies appear to be the same size; therefore, the moon can fit exactly “on top of the sun,” leaving only the corona exposed.
Monday’s eclipse is getting a lot of press, mostly because this is the first time in 38 years that the United States will have a total solar eclipse; that one, back in 1979 only touched a small portion of the North-western part of the country. What’s really got Americans excited is that this eclipse will cross the entire country and it will only be seen in the U.S. The band of totality – the 70-mile wide swath that will get 100% coverage of the sun by the moon – will stretch from Oregon to South Carolina. That’s not happened before in the modern era!
Somewhere on earth, a total solar eclipse happens on average every 18 months, but it’s often in remote areas or in the ocean where few people can appreciate it. Millions of people live along this path of totality, and many millions more live within a day’s drive of it. The next total solar eclipse to touch North America will occur in 2024. That one will travel from Texas to Maine.
Ancient eclipses
In ancient times, an eclipse was thought to bring evil or to be a sign of impending doom. Some civilizations thought a dragon, a jaguar or a wolf was eating away at the sun. In ancient Scandinavia, people believed they had to scare the predator away by making as much noise as possible (luckily, it always worked).
There is a legend that in 2100 BC in China, when the two royal astrologers could not explain why the sun had suddenly disappeared, the emperor had them beheaded!
Around 700 BC, some folks began to think about eclipses in a new way – they started really observing them, and they noticed patterns. The Chaldeans of Mesopotamia kept meticulous records of the stars, the sun and the moon for centuries. These records allowed them to see the patterns, later called Saros Cycles, in eclipses – the cycles last 18 years, 11 days and 8 hours. In 585BC, Thales of Miletus was the first to accurately predict the time and place of a solar eclipse, which, according to legend, was used to end a five-year war between the Lydians and the Medes.
This astronomical understanding proved powerful more than once. In movies, books and even cartoons, quite a few writers have put their hero in a tight spot and then let him use his prior knowledge of a coming eclipse to escape. This overused shtick has its roots in an actual historic event involving Christopher Columbus. He and his men had stranded their caravels on the coast of Jamaica in 1504. They were at the mercy of the indigenous people there, and he had treated them badly enough that they decided to let the strangers starve. But Columbus had an astronomical almanac on board that predicted a lunar eclipse for a coming day, known as the March 1504 eclipse. Columbus used that knowledge to intimidate the locals into giving them food, saying, “If you don’t help us, I will call upon God to destroy the moon.” Thus, he tricked and frightened them into complying, and Columbus and his men lived to tell the tale.
Totality
But I digress. The path of totality for this eclipse will start Monday morning (10:00 pacific time) crossing from Oregon, to Idaho, then Wyoming, Nebraska, clipping the northeast corner of Kansas (about 1:00pm central time) and then into Missouri, just touching the southern tip of Illinois then across Kentucky and Tennessee and then exiting at Charleston, South Carolina. This belt of the moon’s shadow will be about 70 miles wide. Massive crowds of eclipse enthusiasts are expected to flock to this belt of totality. Some people will try to travel along with it across the nation, to maximize their time in totality. The city of Carbondale, Illinois, will receive the longest period of totality, which will be 2 minutes and 18 seconds. That town is expecting about 50,000 visitors for the eclipse. That town’s population will more than double!
In those places, the light will drop to twilight-like appearance and the temperature will drop quickly. Some night time animals may come out. In every direction, the horizon will have the hue of a sunset and the sun will appear as a black circle, surrounded by shimmering silver rays, with some jets of gas reaching far out – this is the sun’s corona or outer atmosphere. Where there are sunspots, similar to storms in the sun’s atmosphere, there can be seen spurts of ejecta escaping the sun’s gravity. These solar flares can travel through space as radiation and they can affect our earth’s magnetosphere and even disturb our telecommunications networks.
84% coverage
Here on the Friendly Island, we won’t get 100% coverage, sadly, but we will be able to notice that something weird is happening with the sunlight. The moon will begin to cover the sun at 2:18pm. Maximum coverage (84%) will be at 3:38pm. The end of the eclipse for us on St. Maarten will be at 4:49pm.
Safety first!
When the eclipse begins, you will be tempted to look up at it, but don’t! This is very dangerous for your eyes. Don’t use a camera without a solar filter, and certainly don’t use binoculars or a telescope. You must use approved protective solar glasses or a #12 or greater welding mask to look at the eclipse, normal sunglasses will not protect your eyes. These special eclipse-grade solar glasses are available at Blue Point and they are made of paper so they don’t cost very much. Make sure your solar glasses are undamaged – a scratch can let in the sun’s rays to hurt your vision. If you are worried about defective or knock-off glasses, check to make sure they have the ISO 12312-2 approval stamp, or put them on and they should be so dark you can’t see anything at all. The sun will appear like an orange circle, similar to a full moon.
By Lisa Davis-Burnett
