An Introduction to the Moon

The picture is big, and there are words below too :)

Well, there it is ... The Moon. The image may look a little unusual, but do not worry. The face on the Moon is exactly as you would see it if you looked at the Moon while in its Full phase. The craters at the poles of the Moon are distorted by the manner in which the moon-orbiting spacecraft compiled the image. You will not see such dramatic cratering with your eyes.

While most people think of romantic walks with their loved ones under the full moon sky in midsummer, others like myself are far more concerned about the darker side of those nights. Supposedly, werewolves roam the forests looking for hapless victims to devour. If you manage to escape the werewolves chewing, you will only suffer from the adverse affect of the bite, becoming a werewolf yourself. To your left is Abbott & Costello when they met Frankenstein, Dracula, and the Werewolf. If you like the Warren Zevon song, "Werewolves of London," then click on the title for the lyrics, or click on his name for the YouTube video and recording. Then everytime the Moon is full, you would turn from the mild-mannered congenial person you are, into a hideous monster, not to mention the effect of ripping your wardrobe to shreds once a month. To help you prepare for the unlikely event when you might encounter a werewolf, I would first suggest you never go to London during a full moon.




If you see one approaching, then you must shoot it with a silver bullet. But since the Lone Ranger no longer is on television, we must assume he has retired, and therefore you have no more access to the silver bullets he made from his silver mine. However, Clayton Moore, the man who played the Lone Ranger used to live right nearby in Golden Valley, and while he was alive you have a chance of getting a silver bullet from him at his house. Sadly, he passed away in 1999. Therefore, I think it best you stay inside the safe confines of your home during a full moon, and do that observation through the window instead.






The basic information about the Moon is captured in a chart seen below:

Moon Facts


7.3483 x 1022 kg

Equatorial Diameter

3476 km

Mean Density

3.34 g/cm3

Acceleration of Gravity

1.62 m/s2

Escape Velocity

1.62 km/s


~407,000 km


~357,000 km

Mean Orbital Distance

~378,000 km

Period or Rotation

29.53 days

Period of Revolution

27.3217 days

Time to Complete a Lunar Cycle

29.5 days



Inclination to the Ecliptic

5.145 degrees

Axial Tilt



The chart above shows information of great interest to me, but typically not of much interest to my students unless they are steered into specific question areas. For instance, "Why is the period of revolution and rotation different but we only see one face of the Moon?" or "What does that mean, inclined to the ecliptic?" or "You mean to tell me that the Moon has gravity ... I thought the Moon was far enough away from the Earth to be in Zero Gravity." The purpose of this unit is to answer some of these questions and share what we have learned about the closest celestial object to us ... Our Moon.

Back to My Little Comments

So, let's say you are out on a date, and the full moon is shining so brightly that it casts a shadow. You look up at the moon and are so mesmerized by its beauty that you forget all about your date. You are enthralled by the subtle shades of gray and the bright rays of a crater near the southern parts of the Moon. You decide right then and there to scrap the date and hurry home to study as much about the Moon as possible and you have found yourself here.

Main Introductory Notes

The purpose of this section is to familiarize students with the Moon, the natural satellite of Earth. To delineate between a planet and a moon, know that planets are objects of respectable size that orbit the Sun. Moons are naturally occurring objects which orbit a planet. Our moon is called Moon, because the name means "night light" in some ancient language. Another term for the Moon could be Earth's Natural Satellite, thus differentiating what has always been up there orbiting our planet from objects that we launch.

The purpose of this section "The Moon" is to familiarize you with the closest celestial object to Earth. It is a airless, waterless, lifeless, geologically dead object. It is roughly the diameter of the width of the United States. It spins very slowly and it orbits the Earth relatively slowly. The result is that only one side of the Moon ever faces the Earth. This side is called the Near Side. The Far Side is a name for the backside of the Moon that we do not see from anywhere on Earth, and also the name of a truly great series of comics by Gary Larson. While Pink Floyd sings about the "Dark Side of the Moon," it is not always dark back there. The Moon is responsible for the tides of our oceans due to the effect of its gravitational attraction on Earth's oceans. The Moon has also be associated with various female dieties of fertility because the lunar cycle is almost identical in length to the cycle of a human female. While this is entirely coincidental, it was considered very important by most older cultures. Lots and lots of great movies featured various lifeforms on the Moon, but nothing could be farther from the truth.

By the time you are done with this section, you should be able to explain to anyone who asks you, what causes the Lunar Phases, Earth's Tides, and Eclipses. You should be able to understand the various theories that attempt to explain the origin of the Moon. You should be able to identify a few major lunar features, and you should be able to know a litle bit about the future of lunar exploration. Other information about the Moon might not be coffee table conversation, but I hope some of it sticks with you. This section is divided into the following parts:

The Moon's Structure and Features - Do this reading on Monday

The Moon's Phases - Work on understanding this process on Tuesday

The Moon's Tides - This gravity lesson is good for Wednesday

Lunar and Solar Eclipses - This lesson ought to be covered on Thursday

Stranded on the Moon ... sort of an assessment ... can be done after you have read this Structure and Features page

Origin of the Moon ... the various theories and the current leading theory (Scientific Method is featured here) ... complete this reading by Friday

Why Are All Craters Round? ... your lab activity, but not required

Moon Observation ... due at a time describe in the main course page

If, at any time, you get lost during this study, you can return to this Introductory Page, or the Space Race, or even the Syllabus, but please go to The Moon's Structure and Features first.

Moon Feature Quiz Link

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