Our Moon: The Familiar Stranger in the Sky

For most people, looking at the moon is such a common experience that we rarely stop to consider it. The moon appears to rise and fall at predictable intervals in the sky. It is easy to take this repetitive behavior for granted. However, if you were to give your attention to the moon, you would begin to understand just how peculiarly unique and interesting our nearest celestial companion truly is.

It averages approximately 238,855 miles away from earth. With that distance, Apollo astronauts were able to travel to the moon in only three days. Our moon was created approximately 4.5 billion years ago shortly after earth. The prevailing scientific theory is a dramatic story involving a Mars-sized object called "theia" colliding with an early earth. Eventually, the pieces of debris from this massive collision would come together to create the moon that we observe today. There is no myth in the fact that the chemical composition of the lunar rocks supports this theory.

One of the most under appreciated aspects of the moon is its size when compared to the earth. The earth-moon system possesses a moon that is abnormally large in comparison to its parent planet. Most other moons within our solar system are significantly smaller in relation to their planets. In reality, our moon is nearly a quarter of the diameter of the earth. Scientists often describe the earth-moon combination as a double planet, which gives new perspective on understanding where we reside.

This size makes a greater difference than you probably imagine. The moon's gravitational influence helps maintain a stable axis on earth (tilted at approximately 23.5°) over extended periods of time. If the moon did not exist and exert this gravitational force upon earth, then the tilt of earth's axis could swing dramatically resulting in climatic variations extreme enough to alter life forms on earth. Therefore, in addition to being beautiful and aesthetically pleasing, the moon has acted as a protector of earth's ability to support life.

In addition to maintaining balance in earth's rotational movements, the moon also exerts significant influences on the oceanic tides on earth. As a result of the moon's gravitational attraction, high and low tides occur throughout each day as well as larger tide fluctuations known as spring tides during alignments of the moon-earth-sun systems. Conversely, lower tide fluctuations known as neap tides occur when the moon-earth-sun alignment produces a right triangle configuration.

Finally, the surface of the moon represents a historical account of violent collisions from eons past. These black areas viewed clearly from earth represent extensive plains of solidified lava called maria. These maria were produced millions of years ago due to volcanic eruptions. The numerous craters covering the remainder of the lunar surface represent remnants of impacts occurring tens-of-thousands to billions of years ago. Due to the lack of atmospheric conditions and minimal geologic processes occurring on the moon, none of these events are erased from view. The moon therefore serves as an open book providing an unedited history of its formation.

Water ice exists on the moon located in permanently shaded regions around the lunar poles. Although first hypothesized in the distant past, recent discoveries within the last decade confirm that ice does indeed exist on the lunar surface. These findings have prompted both scientists and space agencies to reassess their plans for future lunar missions. That ice can potentially be used for producing drinking water or even rocket fuel.

Twelve humans have walked on the moon's surface while visiting earth between 1969-1972. Since then, no human has visited the moon again. One of the more intriguing aspects regarding humanity's continued journey to explore beyond our own world, this void will likely be filled soon as multiple organizations plan on returning to visit our closest celestial neighbor.