Iowa Sky Day

Waning Crescent Moon

My friend E.E. (not her real name) wants to know what I mean by “waning crescent moon.”

This could be a trick. It could be that she already knows the answer and she just wants to see if I do. Or maybe she wants to see me explain it when I’m all goofed up on endorphins. A cruel, devious trick, but I must respond.

When I’m not walking around in a daze pushing a stroller across the planet, I’m a highly qualified credentialed California Geoscience teacher with an M.S. in Geology. I’m supposed to know all that kind of stuff. Actually, every kid I ever taught is supposed to know the lunar phases. (And if you read these posts all the time, I am subliminally teaching YOU…).

So here’s the skinny.

You know that La Luna, the Moon, doesn’t shine. It reflects the light from El Sol, our star, the Sun. From where you are on Earth, you see all, part, or none of the Moon each night, depending on where it is in its orbit around Earth.

When you can see all of it, the whole “face” of the Moon, what we call the Full Moon, the shadow cast by Earth is not obscuring any of the side of the Moon that is facing your spot on Earth.

As it moves in orbit, from your perspective, it wanes, or gets smaller, as it passes into Earth’s shadow. It still looks pretty big. More than half of the face is lit up in this phase, called the Gibbous Moon.

The Gibbous Moon continues to wane until half of the surface facing Earth is light and half is dark. That’s called the Third Quarter Moon (that’s just a quarter of the entire lunar surface – you don’t see the half – or two quarters – of the Moon that faces away from Earth).

The Moon continues to wane from your position, slowly disappearing each night into a smaller and smaller Waning Crescent Moon (think Cheshire cat grin) until one night, halfway into its trip around Earth, it disappears completely into Earth’s shadow.

We call that the New Moon. Why don’t we call it the Empty Moon, you might wonder.

Then it reappears, getting bigger or waxing, into a slowly growing Waxing Crescent until it is in the First Quarter phase (half of the surface facing Earth is lit up, the rest in shadow).

As it continues to wax, more than half of it is lit up. We call that the Waxing Gibbous Moon until eventually it completes its monthly orbit (29+ days) and is once again a Full Moon.

I could have started with the New Moon waxing to First Quarter to Full and waning to Third Quarter to New again, but it’s easier for most folks to imagine a Full Moon. So that’s where I started.

Okay, E.E., that’s my Moonsplaining story and I’m sticking to it. If you don’t believe me, that’s okay, don’t sweat it. The Solar System is 4.6 serious billion years old. We won’t even live for a hundred quick years. It’s okay if you want to think about something else.

Today I walked, in the DAYLIGHT, along old U.S. 6, known locally as White Pole Road, and somewhat officially as the “Grand Army of the Republic Highway.”


I can report that the corn is about calf high. ZZZZZ. I got pretty tired of looking at it so I declared today Iowa Sky Day and just watched the puffy clouds overhead instead.


Like most days, it was a good day to look up.

Peace, Love, and La Luna,

3 thoughts on “Iowa Sky Day

  1. You got that right Mr. Ostdick! To this day I know what “waning crescent” and “waxing crescent” is because of your earth science class in high school. It sure has been helpful. Take care!

    Liked by 1 person

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s