Understanding The Phases Of The Moon
Here’s a “crash course” on understanding Moon phases.
How much do you know about Moon phases? Do you know which phase is invisible to us? Or what the difference is betweent waxing and waning? Here’s a crash course on understanding Moon phases.
Understanding Moon Phases and the Lunar Cycle
First, the Moon is on a 30-day cycle when it makes its orbit around the Earth. Actually, the entire trip takes 29.53 days, to be exact, and is measured from one “New Moon” to the next.
The Phases of the Moon
Here, we’ll break down each of the 8 phases of the Moon as it revolves around the Earth. Refer to the corresponding numbered phases in the diagram above in this article to follow along.
- New Moon. When we are in the “New” Moon phase, the Moon is not visible from our perspective because it is positioned between the Sun and Earth. The portion of the Moon that is actually getting sunlight is the back side of the Moon, the half that we cannot see. It’s called the New Moon because it’s the beginning of the lunar cycle. Push the “reset button” and let the 30-day orbit begin!
- Waxing Crescent – After the New Moon, the Moon continues its journey around the Earth, becoming visible as it moves on its path toward becoming a Full Moon. The sunlit portion is increasing. A crescent Moon is easy to identify as it looks like a sliver in the sky. Waxing = growing in illumination.
- First Quarter Moon. This one confuses a lot of people. In this case, the term is used because the Moon is in the first quarter of the 30-day cycle, but it appears half full. The First Quarter and Last Quarter Moons (both called “half moons”) happen when the Moon is at a 90 degree angle with respect to the Earth and Sun. So we are seeing exactly the half of the moon that gets hit by the Sun’s light.
- Waxing Gibbous – Still growing as we head toward full. More than half of the Moon is illuminated by the Sun. Gibbous = more than half. Waxing = growing in illumination.
- Full Moon. The full Moon comes about 15 days (14.8 to be exact) after the New Moon, the mid-point of the cycle (half of 30 = 15). The Moon is now in alignment with the Earth and Sun again, just as in the New Moon phase, but this time, the Moon is on the opposite side of Earth, so the entire portion of the Moon that is lit by the Sun is facing us. After this phase, which lasts only an instant, visibility starts decreasing.
- Waning Gibbous – Waning = decreasing in illumination as we head toward the darkness of the next New Moon. Gibbous = more than half.
- Last Quarter Moon (sometimes called the Third Quarter Moon). This is when the Moon completes the third quadrant of its phase cycle, about 22.1 days after the New Moon phase. And, as in #3, it looks like a half Moon to us again, except this time, it’s heading toward the New Moon phase (disappearing) instead of growing toward the full Moon phase.
- Waning Crescent – The Moon is a little sliver of a crescent, just as in #2, but the illuminated part is decreasing. Waning = decreasing in illumination. Now, the illuminated crescent is facing the opposite direction as when it was a waxing crescent (see #2).
Two terms to memorize:
Waxing = Growing in illumination
Waning = Shrinking in illumination
How Can You Tell if The Moon Is Waxing Or Waning?
If you look in the sky and see a crescent or gibbous Moon, here’s how to tell if it is in the waxing or waning phase by the direction it’s curving.
So there you have it. We’re happy to answer any questions to help you understand this fascinating and complex changes in Earth’s satellite. Just leave them in the comments below.
Check out our Moon Phases Chart so you can see each phase, day by day, for the entire month!
Want to see the whole process in animation using real images of the Moon? Watch this amazing video courtesy of NASA:
This article was published by the staff at Farmers' Almanac. Do you have a question or an idea for an article? Contact us!
- Farmers' Almanac Staffhttps://www.farmersalmanac.com/author/fa-admin
- Farmers' Almanac Staffhttps://www.farmersalmanac.com/author/fa-admin
- Farmers' Almanac Staffhttps://www.farmersalmanac.com/author/fa-admin
- Farmers' Almanac Staffhttps://www.farmersalmanac.com/author/fa-admin
So should I take my cuttings of plants for propagation on the waxing gibbous moon?
On the dagram above, I think you meant to write that the moon’s orbit around the EARTH is not a circle.?
From what I have just read a new moon is seen every 30 day and the space between the new moons is 28 days? Meaning the new moon is both and ending And a beginning. Thanks for your reply
Very interesting piece on the moon. Now I’m a Moon maniac.
I am trying to understand what “lunar day” it is. If new moon Central time was March 2 @ 11:35 AM, then it would be the first lunar day until March 3 at moonrise, correct?
Then March 3rd, all day/night would be the 2nd lunar day from moonrise March 3 until moonrise on March 4? I am looking at two calendars online that state the lunar day and one of them is wrong. 🙂 thank you for any help.
When is the best time to prune?waning gibbious or waning crescent?
How does the moon phase make deer react
When planting by the moon phases, when is the best time in July to plant peas and beans.
Could someone knowledgeable about timing planting with moon phases give me a quick synopsis? Planting seeds versus plants during waxing and waning of the moon is new to me. But it does make sense. I just can’t remember which gets planted when. Thank you!
Search Results
Featured snippet from the web
In a waxing moon, when light increases towards a full moon, sap flow is drawn up. This is the most suitable time for sowing and transplanting flowering annuals, biennials, grains and melons. … With an waning moon, when the light is decreasing as the moon changes from a full to a new moon, the sap flow is drawn down.Dec 15, 201
Very interesting, thank you
Glad you enjoyed the article, Doris!