By in Humor

When is a Half a Quarter

There is an interesting line in Michael Martin Murphy's song " Carolina In The Pines " that relates to the phases of the Moon. Last night when I looked at the Moon in our clear North Carolina night sky I could see half of the moon and the view got me thinking about the way we describe the phases of the Moon.

When we cannot see the Moon because it is fully in shadow we call it a New Moon. Shouldn't it be called a Null Moon or a No Moon since we cannot see it?

As the Moon begins to emerge from the Earth's shadow and light begins to reflect from a portion of the side facing us, we call that a Waxing Crescent Moon. The word Waxing is used to indicated the lighted portion is growing larger each night.

Now comes the confusing part. When half of the side of the Moon facing us becomes lit we call it the First Quarter Moon. It is called the First Quarter because the Moon is one-quarter of the way through its cycle. So when we see half of the Moon we are seeing a Quarter Moon. This happens again after the Moon is Full and wanes away until only half is left lit. That phase is called the Third Quarter. Again, we see half when we see a Quarter.

Another term that I wonder about concerning the Moon is gibbous. When the lit face of the Moon is between the First Quarter and Full or Full and the Third Quarter it is either a Waxing or Waning Gibbous moon. Where did the word Gibbous come from? I will stop now and look it up so I can tell you.

I'm back and now I can tell you that the English word gibbous comes to us from the Latin word gibbus meaning hump. How exactly that came to describe the view of the Moon between Full and Quarter Phases I have not learned yet. Perhaps I will be inspired to tonight if I catch a glimpse of the Waxing Gibbous Moon.

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Image Credit » by stuzinty

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MegL wrote on October 20, 2015, 6:13 PM

Sounds like a trick question or one of those cryptic crossword clues.

AliCanary wrote on October 20, 2015, 6:24 PM

I understand why what we see as a "half moon" is actually a quarter moon, because we are only seeing half the moon in the first place, and then only half of that is visible. The term I find kind of funny is how we say the dark SIDE of the moon, or the SIDE facing us. Spheres don't have sides!

Feisty56 wrote on October 20, 2015, 7:15 PM

I've never given much thought to these words associated with the phases of the moon. In my simplistic thinking, I assumed ( oh yes, I know) that "new moon" might have been a term used by Native Americans who measured time via "moons."

shaggin83 wrote on October 20, 2015, 8:47 PM

By the time I got to the end paragraph about Gibbous Moon I was laughing. It is no wonder with all these strange terms of the phases of the moon why I have never been able to keep it all straight. You have to wonder when people thought up these names what they were really thinking and since they seem to make no sense why they haven't been changed to easier to understand or more sensible terms over the years.

DWDavisRSL wrote on October 20, 2015, 9:25 PM

It isn't a trick question, but it is a tricky question. You're right, it would make a good crossword clue.

DWDavisRSL wrote on October 20, 2015, 9:27 PM

Then a Full Moon is really a Half Moon. Interesting. Also, I don't know why we call the side of the moon facing away from us the Dark Side as it is lit up part of the time, such as when we have a New Moon.

DWDavisRSL wrote on October 20, 2015, 9:28 PM

Many early civilizations measured time by the Moon and I believe the word moon is the root of the word month. The old Arab lunar calendar was adopted by the Islamic World.

DWDavisRSL wrote on October 20, 2015, 9:30 PM

I'm glad you got a chuckle out of my post. I did agonize over whether or not to post it under Humor. I think the terms are held onto because so much tradition is behind them.

LoudMan wrote on October 20, 2015, 9:56 PM

I find the moon pretty interesting, too. You know, we're going to lose it, one day.

RonElFran wrote on October 20, 2015, 10:01 PM

In reality there is no such thing as a full moon, since you can never see more that half the sphere no matter where you are in relation to it. I guess that's why people decided to call the fully lit side we can see a full moon - it's as full as you can ever see.

wolfgirl569 wrote on October 20, 2015, 10:55 PM

We never see the whole thing so the quarter part makes sense to me. The full moon part does not as that is truly only the half towards us

Paulie wrote on October 21, 2015, 12:12 AM

I have never studied the phases of the moon in detail.

MegL wrote on October 21, 2015, 2:50 AM

DWDavisRSL , I thought it was called the dark side of the moon because we never saw it here on earth because only one side of the moon ever faced us during the illuminated period. AliCanary While the moon is a sphere, we see it as a disc, rather like a plate and a plate has two sides.

DWDavisRSL wrote on October 21, 2015, 6:33 AM

We will if we don't start giving it more attention and show it that we really love and appreciate all it does for us.

All kidding aside, the moon is inching away from us but I doubt I will live long enough to see it depart.

DWDavisRSL wrote on October 21, 2015, 6:34 AM

You are correct as to why we call the side of the moon that always faces away from Earth the Dark Side of the moon. Because the moon's rotation and orbit of the Earth are the same, the same side always faces us.

DWDavisRSL wrote on October 21, 2015, 6:36 AM

This is a reasonable explanation.

DWDavisRSL wrote on October 21, 2015, 6:37 AM

As RonElFran said, it was probably called the Full Moon because it was as full as it would ever get from our perspective.

DWDavisRSL wrote on October 21, 2015, 6:37 AM

Moon phases are part of the sixth grade science curriculum. I taught sixth grade science a few years ago and learned more than I'd ever known about moon phases.

Rufuszen wrote on October 21, 2015, 7:13 AM

I think these things developed to confuse those not having the 'secret knowledge'!

markgraham wrote on October 21, 2015, 1:38 PM

I thought there was what is called a 'Half Moon'.

Paulie wrote on October 22, 2015, 1:30 AM

I wonder why that wasn't taught when I was going to school in the 50s.

Jeramey wrote on October 22, 2015, 2:34 PM

Yes, not only is "month" derived from "moon", but so is another "monthly" thing... the human "menstruation" cycle.

Also, the Japanese word for month is "gatsu" which is one of the readings of the word 月. (Their names are "one month, two month... twelve month, very efficient!)

DWDavisRSL wrote on October 22, 2015, 2:46 PM

I did not realize the Japanese had such a simple system for the months. Do they recognize 12 months like the Western Calendar, or the 13 months of the lunar calendar.

The early Roman calendar had only ten months. They didn't count the winter months.

DWDavisRSL wrote on October 22, 2015, 4:01 PM

A half moon and a quarter moon are actually the same thing. When you use which depends on the context of the conversation.

Jeramey wrote on October 22, 2015, 4:15 PM

Yes, there are 12, but I don't know if that came before or after the Dutch and Portuguese - who are the origins of their names of the week. They used a traditional East Asian classical elements naming system (no Norse gods) but the first two days are "Sun Day" and "Moon Day" so the origin is apparent.

And, yeah, the Romans only needed 10 months when they were a Republic. As emperors Julius and Augustus thought that Sept, Octo, Novem, and Dec should no longer mean 7-10 but 9-12.

markgraham wrote on October 22, 2015, 7:57 PM

Thanks for the astronomy lesson, I really thought they were two separate phases. It has been awhile since I had a Earth/space science class.