Moon Facts and Terminology

waxing moon

Is the Moon in this photo waxing or waning, quarter or gibbous? Look for clues below to answer these questions.

There was that dang Moon again, coming between us and the source of life on this planet, the sun. We watched as the Moon slid from the upper right of the sun until it nearly covered the sun, creating an annular eclipse. At first, I was disgruntled by the cloud cover, but ultimately, we were glad it was there as it made observing this phenomenon much easier to view without special glasses.

This eclipse last Saturday was a great reminder that the Moon is up there and has much more influence on our lives than we might realize. I have talked to credible farmers who are convinced that planting and even livestock management turn out better if the phases of the Moon are taken into consideration. Scientists recognize that some animals time their reproduction to coincide with specific Moon phases. The Moon is also critical for the navigation of many migrating birds. And, according to NASA, “the Moon makes Earth a more livable planet by moderating our home planet's wobble on its axis, leading to a relatively stable climate. It also causes tides, creating a rhythm that has guided humans for thousands of years.”

With the Moon being the brightest object in our night sky, our closest neighbor, and likely even made from a chunk of Earth, it seems that a better understanding of it is in order, so here are some interesting facts and terminology.

The Moon is about 27 percent the size of Earth and is a mere 239,000 miles away (about 10 times the circumference of the Earth). That might sound like a long way, but consider that the sun is 92.709 million miles away and it should seem like we can reach out and touch the Moon. The Moon is 100 times closer than the orbit of Venus, our next closest planetary neighbor.

The Moon spins once on its axis every 27.3 days—the same amount of time it takes to rotate around the Earth, essentially always showing us the same lunar hemisphere. We should thus be fairly familiar with its hard and rocky surface, with its mountains, valleys, “seas”, and plains. Yet when checking a list of the 10 most notable lunar features as selected by the BBC, I could not identify a single one. Can you find any of these on the surface of the Moon—Hadley Rille, Crater Grimaldi, Crater Copernicus, Crater Pluto, Lunar Apennines, the Vallis Alpes, Crater Gassendi, Rupes Recta, Mare Crisium, and the triplet craters, Ptolemaeus, Alphonsus and Arzachel? While the Hadley Rille requires a large scope to see it well, the rest can be seen with a small scope or even binoculars. Shame on me for not paying better attention to my neighbor.

As for terminology, we often talk of the phases of the Moon and most of us have at least an idea what that really means—New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Last Quarter, Waning Crescent, New Moon. The term “waxing” refers to a Moon that is becoming increasingly visible while “waning” means just the opposite and “gibbous” means that the lighted part of the Moon is more than half and less than fully lit. The line where light and darkness meet is called the terminator. Earthshine is when sunlight hits the Earth and is reflected onto the Moon during a crescent phase. The earthshine makes the rest of the Moon slightly visible.

A New Moon denotes a time when we cannot see the Moon. It is the beginning of the Lunar month when the Moon is between the Sun and the Earth, therefore in shadow to us. On a waxing Moon, the crescent faces left (it is on the right side of the Moon) as the right side of the Moon is lighted. It is just the opposite with a waning Moon—the crescent opens to the right and the left side of the Moon is lit. The Full Moon occurs when the Moon and the Sun are on opposite sides of the Earth.

Interestingly, everyone on Earth sees the same phase of the Moon, but those in the Northern Hemisphere see it differently than those in the Southern Hemisphere. For instance, in a waxing crescent phase seen from the Northern Hemisphere, the crescent appears on the right side of the Moon. But in the Southern Hemisphere, it appears on the left side of the Moon. I wonder if that accounts for some of our challenges understanding other cultures.


PHOTO: This is a waxing Moon, probably just past the quarter Moon stage, so waxing gibbous.

Help Idaho Wildlife

When we traveled across the state in October 2017, most of the vehicles we saw using the wildlife management areas did not have wildlife plates. Buying wildlife plates is a great way for non-hunters and hunters alike to support wildlife-based recreation like birding.

C'mon folks, let's help Idaho's wildlife by proudly buying and displaying a wildlife license plate on each of our vehicles! 

See below for information on Idaho plates. Most states have wildlife plates so if you live outside Idaho, check with your state's wildlife department or vehicle licensing division for availability of state wildlife plates where you live. 

And tell them that you heard about it from!

Wildlife License Plates

Idaho Wildlife license plates provide essential funding that benefits the great diversity of native plants and wildlife that are not hunted, fished or trapped—over 10,000 species or 98% of Idaho’s species diversity. Game species that share the same habitats (such as elk, deer, antelope, sage-grouse, salmon, trout) also benefit from these specialty plates.

No state tax dollars are provided for wildlife diversity, conservation education and recreation programs. Neither are any revenues from the sale of hunting or fishing licenses spent on nongame species. Instead, these species depend on direct donations, federal grants, fundraising initiatives—and the Idaho Wildlife license plates.

Both my vehicles have Bluebird Plates. I prefer the bluebird because the nongame program gets 70 percent of the money from bluebird plates, but only 60 percent of the money from elk and trout plates - 10 percent of the money from elk plates supports wildlife disease monitoring and testing programs (to benefit the livestock industry) and 10 percent from cutthroat plates supports non-motorized boat access.

Incidentally, in 2014, the Idaho Legislature denied the Department of Fish and Game the ability to add new plates or even to change the name of the elk and cutthroat plates (very specific) to wildlife and fish plates, a move that would have allowed for changing images occasionally and generating more revenue. It would seem that they believe that we Idahoans don't want a well funded wildlife program.

I think it is time we let the Legislature know that Idahoan support wildlife funding and that we would like to see these generic plates come to fruition.

"WOW. What a phenomenal piece you wrote. You are amazing." Jennifer Jackson

That is embarrassing, but actually a fairly typical response to my nature essays. Since The Best of Nature is created from the very best of 16 years of these nature essays published weekly in the Idaho Falls Post Register (online readership 70,000), it is a fine read. It covers a wide variety of topics including humorous glimpses of nature, philosophy, natural history, and conservation. Readers praise the style, breadth of subject matter and my ability to communicate complex and emotional topics in a relaxed and understandable manner.

Everyone can find something to love in this book. From teenagers to octogenarians, from the coffee shop to the school room, these nature essays are widely read and enjoyed.

Some of the essays here are my personal favorites, others seemed to strike a chord with readers. Most have an important message or lesson that will resonate with you. They are written with a goal to simultaneously entertain and educate about the wonderful workings of nature. Some will make you laugh out loud and others will bring a tear to the eye and warm your heart.

Readers Write:

"You hit a home run with your article on, Big Questions in Nature. It should be required reading for everyone who has lost touch with nature...great job!" Joe Chapman

"We enjoyed your column, Bloom Where Planted. Some of the best writing yet. The Post Register is fortunate to have your weekly columns." Lou Griffin.

To read more and to order a copy, click here or get the Kindle version 


Copies are also available at:

Post Register

Island Park Builders Supply (upstairs)

Barnes and Noble in Idaho Falls

Harriman State Park, Island Park

Museum of Idaho

Valley Books, Jackson Wyoming

Avocet Corner Bookstore, Bear River National Wildlife Refuge, Brigham City, Utah

Craters of the Moon National Monument Bookstore, Arco, Idaho