Tonight is October 8th, which has been declared International Observe the Moon Night (IOMN). Personally, I would choose a date as close to September 13th as possible to take a jab at the late Gerry Anderson and his bit of lunar lunacy known as “Space: 1999”. Yes, I know I missed that date as well on this blog, but I had other issues to deal with. With IOMN clouded and/or rained out tonight for a large portion of the United States, I thought I would provide some educational lunar entertainment to make up for it. So, I dusted off an article I wrote for the Asterism (AAI’s long-defunct newsletter) and I’m using it for material here.
Some years ago, I went to a convention and saw Dee Wallace, best known for playing the mom in E.T. The Extraterrestrial. She was quite nice and she was also there to push DVDs of “The Howling”, a werewolf movie she was in. I took the opportunity to explain to her that I didn’t find werewolf stuff too interesting due to my knowledge of the Moon and the fact that it exerts no strange influences. Dee agreed, but she said that the myths about the Moon were quite pervasive in popular culture, even after the Apollo astronauts walked on the Moon without anything strange happening to them. So, let’s take a detailed look at why the Moon, while interesting, is not mystical.
Time and Tides: People who believe in the mystical powers of the Moon often point out that it could exert its spooky actions through tidal forces. On the surface, this might seem reasonable. After all, anyone who has spent more than a few hours by the ocean or a bay has noticed that the water rises and falls due to tides. Some have argued that, since the ocean is water and people are mostly water in terms of composition, lunar tides should affect people and their behavior. They point to claims of increased weird behavior at times of full Moon and then the old stories always say that werewolves change from people to beasts at full Moon.
However, the “Full Moon effect” has been shown to be false by numerous statistical studies. Also, if one knows how tides work, it is easy to see that they cannot influence living beings. Tides result when the side of an object nearest a gravity source experiences a greater pull than the opposite side does. In the case of the oceans, the sea facing the Moon is about 8,000 miles closer to the Moon than the ocean on the opposite side of the Earth. Since the Moon is about a quarter of a million miles away, the diameter of the Earth is a measurable fraction of that distance and the ocean feels the effect of the difference.
Now, consider the case of a human being. To make things as fair as possible to the werewolf buffs, our example will be a player from the NBA who is seven feet tall. The difference in the pull of lunar gravity between the top of his head and the soles of his feet is so close to zero that it can be considered zero for any practical purpose. Even the varying distance of the Moon from Earth (the Moon’s orbit is slightly elliptical), while important for ocean tides, does not alter this conclusion.
It could be argued that tides do influence some living creatures since a number of sea animals lay eggs at times of very high tides. This is the result of their biological clocks, not lunar influence. And they are not infallible tide predictors as the large number of horseshoe crabs that die stranded on beaches each spring can attest to.
Blinded By The Light: Anyone who has been at an observatory on a public night during a full Moon knows it can appear very bright, especially through the telescopes. This brightness is deceptive. Actually the Moon reflects light about as well as the pavement of a road (an albedo of about 7%). It appears bright because the Moon is surrounded by nonreflecting space, so even a dark object like would appear bright. But that is not the whole story.
It is known that the full Moon appears about ten times as bright as it does at first or third quarter. Before people knew much about the Moon, this must have appeared strange. But there are two reasons for this effect. First of all, during full Moon, the Sun is overhead as seen from the lunar surface. There are no shadows. At other times, there are always some shadows formed by mountains and crater rims. But the other reason was only discovered after the Apollo missions returned lunar samples to Earth.
Most of the Moon is covered in a layer of dust, which is essentially lunar rock that has been pulverized by eons of micrometeorite impacts. When samples of this dust were studied on Earth, it was discovered that there were numerous tiny bits of glass in it. The glass formed as the impacts of micrometeorites melted little bits of surface material. The bits of glass give lunar dust a weak retroreflective property like those reflectors embedded in many roads. Due to this effect, the lunar dust actually reflects a bit more light towards Earth at full Moon.
No Cheese, Green or Otherwise: The final proof against strange lunar influence is the composition of the Moon itself. It is now widely believed that Moon formed as the result of a collision between Earth and a Mars-sized planetesimal in the early days of the solar system, which sent debris from the Earth’s mantle into space.
Because of this origin, only about a dozen minerals make up the Moon. Besides basalt and anorthosite (basic igneous rocks), most of these are oxides of iron, titanium, chromium, aluminum as well as some silicates, along with some minerals rich in potassium and rare earth elements. Recently, something new has been added to this list. In 1998, the Lunar Prospector probe found evidence of hydrogen-rich material in some permanently shaded craters near the lunar South Pole. While it could be buried water ice from ancient comet impacts, hydrated minerals and cometary hydrocarbons have not been ruled out. While this mix of minerals is interesting to those who want to build lunar bases, it is about as non-mystical as one can get.
As one can see, the Moon is an interesting place with great potential importance for humanity’s future. Now, isn’t this far more interesting and exciting than mysticism and werewolf stories?