The things we’re closest to we often seem to take for granted. Or ignore. It took me more than 30 years to drive one hour from my New Jersey home to visit Ellis Island, the small spot of land where my father had taken his first steps in America. I just didn’t make the
time to see it because it was just down the road. It’s the same in Arizona and everywhere else. The wonders in our own backyard just don’t seem as special as the wonders found elsewhere.
And so it is with astronomy. I go outside and search for some far away object that appears as a smudge, a nothing. And yet, on almost any given night, close enough to marvel at with
just the naked eye, close enough to see more detail than any of the planets can ever reveal, is the moon. I’ve promised myself too often to make it a focal point of my sky watching. Maybe I’m finally old enough to stop taking this beauty for granted.
Formed quite possibly from a massive collision between an ancient Earth and another massive object, the moon has been our companion for approximately 4.5 billion years. Roughly every 28 days it circles our home, going through totally predictable phases. Its
orbit is synchronous with its spin, an incredible phenomenon that prohibits us from ever seeing its “dark side,” unless in photos, or if we’ve been fortunate enough to have been an
astronaut on a lunar mission.
An easy experiment proves this. Take two balls to simulate the earth and moon. Conduct two lunar “orbits.” On the first, keep the moon from spinning on its axis and observe how
its entire surface will become visible to Earth during its 28-day voyage. On the second “orbit,” very slowly spin the moon so that it completes one full turn between the beginning and end of the 28-day cycle. As you can see, only one side will face the earth.
Now, take your experiment a bit further. With two helpers, head to a dark room and use a strong flashlight as a makeshift “Sun.” This demonstration will show how and why we see the famous lunar phases. Keep in mind that the sun, earth and moon are never in a straight line except during lunar or solar eclipses. One of your helpers will handle the flashlight. While you serve as the earth, your second helper will walk the moon in an orbit around you. Keep the sun in a fixed position while moving the moon around the earth. As the earth, turn just enough to see the way the light bounces off the Moon as it completes its orbit.
Your flashlight can be kept at a considerable distance. The sun is, after all, 93 million miles away, while the earth and moon are separated by approximately 250,000 miles.
As the moon orbits you’ll notice that when it is alongside the earth it is in its “quarter” phase. When it moves furthest from the sun it is in “full” phase and when it is closest to the sun it is in its “new” phase, with only the side facing the sun getting any of the sun’s light. Another way to look at it is to say that the three and nine o’clock positions are quarter phases, the 12 o’clock position is when we see a full moon, and the 6 o’clock position is when none of the moon will be visible because the surface facing us is not receiving any light from the sun.
A third experiment simulates eclipses. First, place the moon directly between the sun and the earth. Part of the Earth will be in shadow. This is a solar eclipse. For a lunar eclipse,
allow the earth to block the light of the sun, leaving the moon almost hidden, picking up just enough ambient light to be found.
It’s been 50 years since a couple of men first walked on the moon. On July 20, 1969, my father and I watched the event in real time. I remember asking him if he had ever thought this could happen in his lifetime. He replied quickly, “No.” The word “impossible” fell out of style that night.
So, for me, 50 years later, I hope I’ve finally learned to keep my sights a little closer to home. I’m determined to learn more about the earth’s celestial neighbor, to try to recognize some of its features and to stop taking for granted what is closest and most familiar. Maybe all of this will serve as a reminder to me to do the same with the people and places that impact me so profoundly on a daily basis.