On Monday, August 21st we have the Great American Eclipse happening. It is a pretty exciting thing indeed to have such an event taking place across the entire continent of North America. With that in mind, I have been thinking on it quite a bit… and honestly, I have one major question.
But, before I ask my question we need to clarify how it all works. Bear with me for a moment while I try to elaborate on what we need to know to grasp how these bodies orbit or spin in relation to one another. Hopefully this is written in a way that it isn’t too hard to follow.
So… here we go.
To make one complete rotation in 24 hours, a point near the equator of the earth must move at close to 1,000 miles per hour (1,600 km/hr). The speed gets less as you move north, but it’s still a good clip throughout the United States. With that being the case, for simplicity sake, we will say that the earth spins at 1,000 miles per hour while making one full revolution within a 24 hour period. Within the course of one full rotation, the earth spins a total of 24,000 miles in 24 hours (seems simple enough).
The Moon orbits the earth at a speed of 2,288 miles per hour (3,683 kilometers per hour). During this time it travels a distance of 1,423,000 miles (2,290,000 kilometers) for one full revolution. The sidereal month is the time it takes to the moon to make one complete orbit around Earth. This is about 27.32 days. The synodic month is the time it takes the Moon to reach the same visual phase. This varies notably throughout the year, but averages around 29.53 days.
This would mean that one full revolution for the moon takes close to 27 or 30 full 24 hour periods. This would then further imply that the earth would in essence spin on its axis a total of 27 to 30 times while the moon itself completes one single revolution. In other words the moon during one full 24 hour period would have traveled only a total of 54,912 miles. This is roughly 1,368,088 miles shy of completing one full revolution.
To better grasp what I am getting at, the following video is a great animated visualization of these two bodies and their respective speeds of motion (the earth spinning on its axis and the moon orbiting the earth). This video makes it seem a lot less complicated than I just did, for sure.
In this video you will notice that both bodies are moving from West to East. The earth spins on its axis in an eastward direction. The moon orbits the earth in an eastward direction as well. With that in mind, both of these objects move from west to east in their respective speeds. This is something we can all agree upon I hope. The earth is going one speed. The moon is going another speed. They both travel in the same direction.
Seems simple enough…
There is however a major error that occurs when you consider the two speeds and the fact that the earth is generating a full revolution at more than 27 times that of the moon’s speed. As a result, although the Moon is moving to the east relative to the earth, the much faster westward motion of the sky is carrying it to the west, so despite its eastward motion relative to the center of the Earth, it rises in the east and sets in the west, just like any other celestial body.
To better grasp what I am rambling about, go back and watch that video again. You will notice that although the earth and moon are both traveling eastward, the earth’s greater speed is causing the moon to appear to travel east to west rather than west to east in relevance to the observer from ground level on the earth.
The point here is simply this; although the moon travels from the west in an eastward direction, the earth spins so fast that it causes the observer from ground level to see the moon traveling backwards from east to west instead. With this in mind, go back and watch the animation one last time to see what I am talking about.
Now, assuming that I haven’t lost you… here is the question.
Despite the fact that both the earth and the moon are traveling from west to east, the relative motion of both bodies causes the moon to appear to be traveling backwards from east to west. If this is the case (which it is) please… someone explain to me how in the world is the Great American Eclipse on the 21st is apparently occurring from West to East?
This absolutely defies the Copernican Principle.
Again, if the moon due to relativity appears to the observer to be traveling from east to west, how in the world is this eclipse happening from west to east? Someone, please explain to me how this doesn’t totally disprove the Copernican Principle of Heliocentric Cosmological Evolution?
This eclipse is only going to last like 4 hours across the United States. But before we look at the math behind this… let’s let Neil Degrasse Tyson explain real quick how math surpasses our senses. Don’t trust what you can see, touch, or feel… No, instead, trust the math.
With that in mind, let’s look at some math real quick. In order for the moon to defy our senses, no longer appearing to travel from east to west despite the fact that it supposedly isn’t, it would inevitably need to somehow speed up and begin traveling in an eastward direction faster than that of the earth’s spin.
And since it will only take 4 hours for the moon to cross North America on the 21st, this would then mean that the moon is somehow no longer traveling (according to math) 1,423,000 miles in the course of 720 hours. No, instead… on the 21st it will magically have sped up from 2,288 miles per hour to a whopping 69,644 miles per hour so as to defy the east to west observational conundrum.
Hhhmmmmm… I don’t know why, but this bible verse seems to come to mind.
And there shall be signs in the sun, and in the moon, and in the stars; and upon the earth distress of nations, with perplexity; – Luke 21:25
Who are we kidding though, I am clearly just ignorant.
To the average observer here on earth the moon travels from east to west. But, on the 21st it will be doing its own thing. Don’t worry about it. Just let the math do the talking. Like Neil Degrasse Tyson said, we can’t trust what we see anyway. The science guys will explain this one away. Keep on letting them do your thinking for you.
What does NASA have to say?
Whatever… rant over.
Space is fake.