Introduction to Solar Eclipses

Solar eclipses occur when the moon passes between the earth and the sun, blotting out the sun. This causes a shadow to cast on the earth in a small area. It is similar to when a cloud passes between you and the sun or when you move behind a building into the shade. But these similarities are slight - the shadow of the moon covers a swath on the earth's surface that can be thousands of miles long.

There are actually several types of eclipses. A partial eclipse occurs when the moon passes in front of only a part of the sun, as viewed from your location on Earth. A partial can sometimes develop into a totality. An annular eclipse occurs when the moon passes directly in front of the sun but is too far away from the Earth, and is thus too small to block out the entire disk of the sun. Finally, the event occurs when the moon passes directly in front of the sun and is close enough to the Earth to cast a large shadow. This is the major league event that you'll want to see. All other events, including lunar events, are minor in comparison.

Time to Prepare for the Total Solar Eclipse

August 21, 2017 - Total Solar Eclipse Planning Guide
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People who happen to be in the path of the totality see many oddities that can be explained but are best experienced personally. Despite the path of the moon's shadow being thousands of miles long, it is quite narrow, perhaps only 50 miles. It also is a fleeting show since the shadow travels so quickly. That makes it quite rare for people to have experienced such the effects as they stood in the shadow.

To get the real effects, you have to be in that narrow band. Just being close is no good. The most amazing features can only be seen in the narrow path of totality. The area is small, the event is a rare occurrence and much of the Earth is covered in water. These factors greatly reduce the chance of people seeing the wonders of this most amazing natural spectacle.

Why Doesn't Totality Happen All the Time?

After all, the moon revolves around the earth every month

While the moon circles the earth each month, there are often no types of eclipses at all. The moon has a slightly erratic orbit around the earth. This means that the shadow cast by the moon might pass over or under the Earth. As well, the moon is quite small in the sky. This means that the moon is sometimes a little too far from the Earth and won’t cover the sun completely. In these cases, there can be a partial solar event but not a total.

Even if there is a totality event, there may not be people in the path of the moon’s shadow. If the shadow path covers areas in the expanse of the ocean, only people on ships or airplanes will experience the spectacle. If the path travels across the arctic areas, few people would witness the event. Because of the attractions, however, every modern occurrence will be witnessed first hand by a few hardy travelers regardless of where the shadow of the moon touches the earth.

Luckily we can predict the exact date and time of the future totalities. This gives us the ability to select a particular event to view, determine where to go to see it and know exactly when to expect the various phenomenons to occur.

What Effects Can You Expect

It Doesn't Just Get Dark

When a solar event is happening, the sky will get dark, but it is unlike a regular night. Because the totality path is so narrow and small, there is a lot of sunlight beaming onto the earth near each observer. It does get dark, however, which affects animals and insects. Birds will head to their roosts. Animals will want to go to their stalls even if they have only barely woken in the morning. Nocturnal insects and animals will emerge.

As the time approaches, there is much less solar energy reaching the area of the earth that will be eclipsed. This often has the effect of stalling the weather for a while. Clouds which were moving will slow or stop as the wind abates. The temperature will drop significantly, especially on a hot day. You will be able to see the shadow of the moon racing across the landscape if there is a view of the distance.

Prior to totality, you may be able to look at the shadow thrown by a tree onto the ground. Often thousands of small images of the sun in partial eclipse will be visible. These are caused by the gaps in the leaves of the tree acting as a multitude of pin hole cameras. By paying attention to these effects as the time of the main spectacle draws near, you can experience things that are often overlooked by more casual observers.

If the weather appears bad in your immediate area, you may want to quickly move to another vantage point if you are able. This is best done by car. Unfortunately, many eclipse viewers have been clouded out at the last possible moment. It takes a surprisingly small cloud to ruin the spectacle of a total eclipse. It will still get dark, and there will be things to see, but the true majesty is only revealed if you are lucky enough to have good, sunny weather during the eclipse phases.

When is the Next Solar Eclipse in the United States?

August 21, 2017

On August 21, 2017, a totality will traverse the United States from Oregon to South Carolina. This event will last the longest at Hopkinsville, Kentucky, 2 minutes and 40 seconds. This will be the first one to occur in the United States since July 1991. Luckily the wait for the next one won’t be as long.