Tag Archives: amateur astronomy

Lunar Mythbusting

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?

Is Resistance (to Light Pollution) Futile?

For the benefit of the few readers of this blog who may not be familiar with the term, light pollution is excessive and misdirected outdoor lighting that makes it difficult to impossible to observe objects in the night sky.

With the definition out of the way, some organizations such as the International Dark Sky Association and Globe at Night claim that their efforts to raise awareness of this issue have met with a measure of success.  While this may indeed be the case, I think the progress has been minimal.

One example concerns Earth Hour, which was from 8:30 PM to 9:30 PM on March 28th.  What is supposed to happen during Earth Hour is that people are supposed to shut off their outdoor lighting for the duration.   Instead, very little of the sort actually happened as is usual for every year this event has been held.  The lamestream media did give it some mention and pointed out that some towns and cities celebrated it.  These “celebrations” were quite noncommittal and merely involved turning off the outdoor lights around a prominent local landmark or two.  Besides this governmental involvement, nobody appears to have done anything.  Yet, when there is an occasion that asks for people to turn lights on, such as the National Night Out held every August, the level of participation is very high.  Apparently, people have a strong aversion to turning off their outdoor lights even though it costs them money for the electricity and the security benefits are limited (according to sources such as the FBI).

What I would like to see is a city or town decide to celebrate Earth Hour with a partial reenactment of a World War II-era blackout.  Younger readers of this blog might not be aware that, during the war, people were in fear of being bombed at night by the enemy.  For the British, this fear was very real as the Luftwaffe frequently bombed targets in Britain under the cover of night during the early part of the war.  In the United States, the fear was more hypothetical as the capabilities of the enemy were not well known.  While the country was definitely out of range of German aircraft, the range of the Japanese planes was largely unknown in the early days of the war and there was speculation that they could reach targets on the west coast.  To frustrate night bombers, towns and cities adopted a blackout strategy where, when a signal was given, every source of possible outdoor illumination was either shut off or completely shielded.  While this was not 100% effective in Britain (the Germans had an early sort of radio navigation), it did make it harder for British cities to be struck, and in the United States, blackouts did raise war awareness among the public.  Getting back to the main point of the paragraph, towns and cities should celebrate Earth Hour by turning off as much outdoor illumination as possible (except traffic signals) and possibly even compete with one another for achieving the greatest light reduction.

Another example was a recent news article that carried a night-time satellite image of the Korean peninsula.  South of the 38th parallel, there were brightly lit cities and towns.  North of it, almost complete darkness.  The author of the article was implying that light pollution is a sign of economic vigor and is a good thing, despite growing evidence of health and ecological problems it causes.  By not having light pollution, North Korea was dysfunctional.  Actually, one doesn’t need a satellite image to figure that out.  Any society where the police manual has a chapter devoted to cannibalism has very serious problems and lighting is not going to fix that.

However, for any serious progress to be made against light pollution, there would need to be a change in mentality that I do not see happening.  An example of the kind of thinking that helps perpetuate light pollution was aired on my local AM radio station.  Every Wednesday morning, they have a short (about forty minutes) program hosted by Milton Paris, titled “Getting Ahead in Business”.  Each program, Paris would bring on a business owner that he met at one of his public functions and that owner would describe his business while Paris would ask questions and make favorable comments.  Recently, he had the owner of a sign company and the two of them waxed rhapsodic over illuminated business signs.  The part that caught my attention was when they said that it made good sense to leave said signs on all night as advertising.  Aside from the obvious contribution to the light pollution problem, such an approach would be wasting money for those businesses since they would be spending money on electricity to power the signs when there is nobody around to see them.  While I am not advocating doing away with illuminated business signs, nor am I against their use for advertising, I believe that an intelligent business would have them shut off after a certain time when potential viewers of the signs are not around.  After all, a sign shining at three in the morning is not likely to be seen by anyone except the occasional over-the-road truck driver or police officer on patrol.  In short, why pay to put on advertising when there is no audience?

The point of all this is that there cannot be much real progress against light pollution until the mindset of leaving lights on all night even when there is no need for them is changed.  Does anyone see any way to change that?