It’s almost here! The Great American Eclipse occurs on August 21, 2017 (Monday!). Are you ready? Are you excited? Do you care? If you are not waiting with great anticipation for this celestial event, I’ve written this for you. If you do “get it”, like I do, please read on and nod your head with deep appreciation and approval.
As I have explained to people my plans for the Great American Eclipse, I quickly understood that most people are not like me. It would usually go something like this…I would begin to tell them my plans and they would smile with a look of disbelief in their eyes. They are generally polite and would not ask the question I know they are thinking (“Why?”). Furthermore, I would usually sense something like pity in their eyes.
Yes, I am a geek. I think stuff like this is cool which often made me uncool growing up. I’m the kind of person that would argue the Apollo 8 flight was the most significant of the Apollo series, not Apollo 11 (first moon landing). I started making plans and reading articles about the Great American Eclipse well over a year ago. I am driving my wife and kids a very long way to see something that will take just over two and a half minutes (being directly in the moon’s shadow…the path of totality).
And, I might add, historical weather data tells me there is only about a 40% chance the weather will cooperate (clear skies). Please read on, if only because you are curious at why people like me are so enthused about a shadow.
A “Coincidence”
Have you ever noticed that the sun and the moon appear to be the same size? Why is this? I know from science class at some school in my past that the moon is about 1/6th the size of the earth and 1.3 million earths could fit inside the sun. Everyone knows that, right? Therefore, it is not a stretch to say that the sun is much, much larger than the moon. In fact, the sun’s diameter is 400 times larger than the moon. Interestingly, the sun is also 400 times farther away from the earth than the moon. 400.
The relative diameter and distance to the earth of the sun and the moon is 400. Because these ratios are the same, the sun and moon appear to be the same size as viewed from the earth. Why should these ratios be the same? There must be some amazing explanation for this, right? I searched and searched for a scientific explanation and what I found may surprise you. It is just chance, an accident, a coincidence, a serendipitous fact, a fluke, luck…it is just the way it is.
So they say. Well, I have a slightly different explanation than pure dumb luck — but more on that later.
What are the odds of this? I can tell you that no other planet in our solar system has this unique combination of moon size and planet to sun distance to experience what is going to happen here on August 21, 2017. We live on a very privileged planet for many reasons and you can add one more to the list because it is this “coincidence” that makes a total solar eclipse so spectacular.
Before I go any further, let us get some definitions out of the way. Solar Eclipse – As seen from the earth, is the type of eclipse where the moon passes between the earth and the sun and the moon partially or fully blocks the sun from the viewer’s perspective. Partial Solar Eclipse – Occurs when the sun and the moon are not in perfect alignment with the viewer on earth and the moon only partially obscures the sun.
Annular Solar Eclipse – Occurs when the sun and the moon are in perfect alignment with the viewer’s location on earth but the apparent size of the moon is slightly smaller than the sun leaving only a bright ring (annulus) visible from the earth. Total Solar Eclipse – Occurs when the sun and the moon are in perfect alignment with the viewer’s
location on earth and the apparent size of the moon is slightly larger than the sun completely blocking its light within a narrow band on the earth (path of totality). You will notice I included the phrase “viewer’s location on earth” in my definitions. It is not enough to be on earth. You must be at the correct location on earth. Whether there is an annular or total solar eclipse is due to the elliptical orbit of the moon. When the moon is closest to the earth in its orbit, it is about 225,000 miles from the earth (perigee) and it appears a little bigger. When the moon is farthest from the earth, it is about 252, 000 miles from the earth (apogee) and it appears a little smaller.
This 27,000‐mile difference is the difference between an annular or total solar eclipse. 27,000 miles may sound like a lot but compared to the 93,000,000 miles from the earth to the sun, it is quite small (about 0.03%).
How Rare Are Total Solar Eclipses?
Are total solar eclipses rare? Yes and no. A total solar eclipse happens somewhere on earth about every 18 months. That is probably more frequent than you thought. Disappointed? Consider this, the path of totality (width of the shadow) is quite narrow. The maximum width of totality for the August 21st eclipse is 71 miles. Because of this narrow band, it does not cover much area relative to the size of the earth.
For any single location on earth (where you are standing right now, for example), on average it will experience a total solar eclipse once every 350‐400 years. Now I’ve got your attention. The last total solar eclipse in the continental United States was on February 26, 1979. The path of totality went through the states of Washington, Oregon, Idaho, Montana, and North Dakota. While this was truly amazing for all the wildlife that got to see it, this eclipse did not reach a large portion of the population of the country. The total solar eclipse prior to the 1979 event was on March 7, 1970 and went from the southeast up to the mid‐Atlantic states. The last total solar eclipse to make a coast to coast path like the August 21st event occurred on June 8, 1918.
The continental United States gets a total solar eclipse about every couple of decades but it has been more than 38 years since the 1979 eclipse that dozens of people got to see. If you add in all the technological advancement in the last 4 decades, you can understand why the August 21, 2017 total eclipse is being called “The Great American Eclipse”. It will likely be the most viewed, photographed, talked about, etc. eclipse in human history.
Fortunately for those of us in the continental United States, the August 21, 2017 event will be followed by another total solar eclipse 7 years later (April 8, 2024). Do you live in or near Carbondale, Illinois? If so, you are truly blessed. The paths of totality for both events (2017 and 2024) cross just a bit south of Carbondale.
How Great Could It Be?
Although I have not seen one yet, I think I can safely say that if you have not been in the path of totality, you have not seen the real thing. The difference between a partial or even an annular eclipse and a total eclipse is night and day (wink). I read one account from a man who has experienced more than 20 total solar eclipses around the globe. He said that on a scale of 1 to 10 of natural phenomena, a partial eclipse is maybe a 4. He said that an annular eclipse is around a 9. An annular eclipse is an extraordinary experience. You can see the ring of fire and significant dimming of the sunlight. It is certainly an event to remember.
Then there is the total solar eclipse. He said that it is not even on the same scale. There is no comparison that can be made. On a scale of 1 to 10, a total solar eclipse is a 100. It is a spectacular thing to experience. I purposefully did not say that it is a spectacular thing to “see” because a total solar eclipse encompasses all your senses.
Total Solar Eclipse Observations
Let us suppose you are in the path of totality and you are also experiencing a clear day on August 21st, 2017. What exactly are you going to experience?
*The eclipse will begin innocently enough as the moon begins to cross the face of the sun almost 90 minutes before totality begins. There will be a slow, largely unnoticeable dimming of sunlight during this time until the sun is just a tiny sliver as the moon’s shadow races toward your location.
*Animals and birds may display unusual behavior as they prepare for nightfall. For example, birds may return to roost.
*The moon’s shadow is moving across the face of the earth at more than 1,400 miles per hour (relative ground speed) in the southeastern United States for the August 21st eclipse. Therefore, totality only lasts a few minutes. As the moon’s shadow reaches your location, you will be plunged into sudden darkness. It will be obvious. This is the only time at which it is safe to look at the sun without protection.
*The moon will look like a hole in the sky surrounded by the glowing sun’s corona.
*Stars and planets will be visible.
* The temperature will drop noticeably, perhaps as much as 10 to 15 degrees Fahrenheit within a short amount of time.
*Then, as quickly as it rushed upon you, the shadow will leave and it will be light again and the process will go in reverse until the moon has completed its trek across the sun.
About That Coincidence
Did you know the moon is leaving us? As it is with life in general, things change. Currently, the orbit of the moon around the earth is increasing at a rate of about 1.5 inches per year. As the moon moves farther away from the earth, it will appear smaller and mess up our perfect ratio. The moon will no longer appear the same size as the sun. Does this make you sad? Don’t worry. At this rate, it will take 50 million years before total solar eclipses are no longer possible because the moon will not appear large enough to blot out the entire face of the sun.
Am I making too much of this “coincidence”? If you think so, do an internet search on “total eclipse coincidence” and you will see that there has been much written on it. In Scientific American, Caleb A. Scharf wrote an article titled “The Solar Eclipse Coincidence” (May 18, 2012). His closing paragraph is as follows:
So is there some great significance to the fact that we humans just happen to exist at a time when the Moon and Sun appear almost identically large in our skies? Nope, we’re just landing in a window of opportunity that’s probably about 100 million years wide, nothing obviously special, just rather good luck.
I understand the point of view expressed in this article but I do not agree with it. I am a Christian. I believe that “In the beginning God created the heavens and the earth” (Genesis 1:1). I do not worry too much about the “how” part. I believe He did it. Devoid of God, the conclusion expressed by Mr. Scharf makes perfect sense. But consider:
God made the two great lights, the greater light to govern the day, and the lesser light to govern the night; He made the stars also. God placed them in the expanse of the heavens to give light on the earth, and to govern the day and the night, and to separate the light from the darkness; and God saw that it was good. (Genesis 1:16‐18)
When I consider Your heavens, the work of Your fingers, the moon and the stars, which You have ordained (Psalm 8:3). The heavens are telling of the glory of God; and their expanse is declaring the work of His hands. Day to day pours forth speech, and night to night reveals knowledge (Psalm 19:1‐2). Great are the works of the Lord; they are studied by all who delight in them. Splendid and majestic is His work, and His righteousness endures forever. He has made His wonders to be remembered; the Lord is gracious and compassionate. (Psalm 111:2‐4) “Can you bind the chains of the Pleiades, or loose the cords of Orion? Can you lead forth a constellation in its season, and guide the Bear with her satellites? Do you know the ordinances of the heavens, or fix their rule over the earth?” (Job 38:31‐33).
Experiencing an eclipse is not something that should make you feel lucky, it is something that should make you feel blessed and thankful to the One who created all that there is. On August 21, 2017, from 2:40:50 pm to 2:43:25 pm, I’m sure I will be experiencing many emotions as I enjoy this event with my wife, kids, and other family. I can assure you that above all, I will be giving thanks and praising the One who made it possible. He made sure that the diameter of the moon is exactly 400 times smaller than the sun and that the moon is exactly 400 times closer to the earth than the sun.
A total eclipse is not a coincidence. It is how He made it. Perfect.