What is a “Cheese Moon”?

31 July 2014

The Short Answer (TSA)

. . . or is it “Moon Cheese”? What is “Moon Cheese?” Well, it’s “natural” and it’s "crunchy." Hey, wait. That’s a snack food. Opps, excuse me, its actually pure cheese from which all the moisture’s been removed. But, hold on. None of the flavors (it comes in three flavors) look green.

Let’s get back to the cheese moon.

Green Cheese Moon?

Did anyone ever really think that the Moon was made of green cheese?

Well, no. The expression “the moon is made of green cheese” is actually part of the legends and folklore of a number of cultures. And, the expression has always meant about what it means, today. A person who believed that the moon was made of green cheese was . . . well, . . . “a few cans short of a six-pack” if you know what I mean.

The old legends always had the same basic story line. A not-so-bright character sees the reflection of the moon in a pool of water (or pond, river, stream or well) and thinks it’s a large round block of cheese. Then, the mistaken viewer tries to get the cheese, falls into water, and almost drowns.

In most versions of the story, the hapless cheese-chaser is encouraged to believe the reflection is really a cheese by a clever passerby or companion. The clever deceiver, then, convinces the cheese-chaser to leave some valuable property on shore. Then, the companion makes off the abandoned valuables when the cheese-chaser falls into the water.

Several hundred years ago, “the moon made of green cheese” became proverbial in western literature. To hoax, con, or fool someone was often referred to as trying to make a victim believe that “the moon was made of green cheese.”

Another question. Why is the cheese green?

There’s no type of cheese that’s actually called green cheese. Blue is the closest color-name I found associated with cheese. To be honest, some “blue” cheese looks a bit blue-green to me. So, it may be possible to find some examples of green colored cheese, but no cheese-maker will claim the color green by name.

But in the old legends and folktales, “green” didn’t refer to a color. Instead the word “green” referred to the age of the cheese. A “green” cheese was a cheese that had not been aged yet.

Since an un-aged cheese isn’t actually the color green, what does a green cheese look like? It’s white and has the consistency of cream cheese. And that’s the point. The reflection that our easily fooled cheese-chaser would have seen in the water wasn’t the color green. Instead it was the reflection of a normal, white full moon, which he foolishly mistakes for a round block of un-aged cheese and tries to go after it.

So, in the end, we can conclude that absolutely no one has ever really believed that the moon was actually made out of cheese of any color. Right?

Well, not so fast. At least one commentator claims that the moon is made of cheese. Worse, there is a “cover up.”   Both NASA together with Google Moon (it’s just like Google Earth only with views of the Moon) have conspired to ingeniously conceal the Moon’s true . . . consistency or composition or something.

This spells real danger for the next astronauts who may, someday, visit our dairy-product satellite. I’m not sure that the theorist is entirely serious about all this, but a landing module could sink far and fast in a tranquil sea of cream cheese.

Our next lunar astronauts might be well-advised to secretly store a large quantity of crackers on board – just in case they are forced to eat their way out of the cream cheese version of quicksand.

Please read: Is the moon made out of cheese? [humor]

M Grossmann of Hazelwood, Missouri
(& Belleville, Illinois)
31 July 2014
About the Author

What is a "Blue Moon"?

24 April 2014

THE SHORT ANSWER (TSA)

A “Blue Moon” can be 1 of 3 things.

First, a “Blue Moon” means “a really rare event.”  The phrase, “once in a blue moon,” refers to a rare event that happens only once in a great while.

Second, a “Blue Moon” is a somewhat rare event involving the actual Moon.  I’ll call the "Blue Moon," the “extra” moon. 

Rarely, there can be 2 Full Moons in the same calendar month.  When this happens, the 2nd Full Moon in that month is called a “Blue Moon.” But that extra Full Moon “throws everything off,” and we get more "Blue Moons."

If 2 Full Moons fall in the same month, then, there will 4 Full Moons (instead of 3) in that season of the year, Spring, Summer, Autumn or Winter.  The 4th and last (or extra) Full Moon in that calendar season is also called a “Blue Moon.” 

But wait, there’s more.

If 2 Full Moons fall in the same month, then, there will be 13 Full Moons (instead of 12) in that year.  What do you think they call that last, the 13th, Full Moon in December?  You guessed it.  That last Full Moon of the year is also called a "Blue Moon."  

So, if we’re talking about the actual Moon, there are 3 kinds of "Blue Moons." A "Blue Moon" is:

(1) the second Full Moon falling in a particular calendar month.  (There’s usually only 1)

(2) the fourth Full Moon falling in a particular calendar season of the year.  (There’s usually only 3)

(3) the thirteenth Full Moon falling in a single calendar year.  (There’s usually only 12)

The next time there will be 2 full moons in a single month will be in July of 2015 with Full Moons on July 2nd and July 31st.   The 2nd Full Moon in July, the Full Moon on July 31st, is a “Blue Moon.” 

July is part of the summer season.  So, in the summer of 2015, there will be 4 Full Moons instead of 3.  The 4th (and last) Full Moon of the summer falls on September 13, 2015 and is another "Blue Moon."  

Since this particular July falls in the calendar year 2015, there will 13 Full Moons in 2015 instead of the usual 12.  That last, 13th, Full Moon on December 11, 2015 is also a “Blue Moon.” 

Again, I think of the “Blue Moon” as the extra “Full Moon” at the end of the line in a particular month, season or year.

Oh!  I almost forgot . . .

Third, the phrase “Blue Moon” also describes a Full Moon that’s actually the color blue.  Major volcanic eruptions or forest fires can fill the atmosphere with so much grey dust that Moon will seem to have a blue-ish tinge:  A blue moon.

M Grossmann of Hazelwood, Missouri
(& Belleville, Illinois)
24 April 2014
About the Author

What is a “Blood Moon”?

24 April 2014

THE SHORT ANSWER (TSA)

Blood Moon / Lunar Eclipse

            No one is exactly sure what a “Blood Moon” is.  The term sounds like it must come from ancient mythology or legends, but it doesn't.  Actually, it’s quite new.  With the recent lunar eclipse, the term “Blood Moon” suddenly became “all the rage” with everyone describing the eclipse as a “Blood Moon.”

Blood moon: Lunar eclipse gazers mesmerized as red hue lights up sky  [story & video]

            A lunar eclipse is a sudden darkening of the, otherwise, full moon caused by the earth coming between the Sun and the Moon.  In other words, the earth casts a shadow on the moon causing it to suddenly “disappear”

            But not quite.

            Those of us who have seen a few lunar eclipses can tell you that the moon never completely disappears during an eclipse.  First, a thick, dark grey, smoky-looking shadow creeps over the moon.  But just behind the edge of the creeping darkness you can make out a dim, but distinctly visible, round moon.  But this darkened moon always has a dark reddish color.  So, every eclipse produces a very dim, dark-red moon.

            Even though no one has ever called it a “Blood Moon” before, the name is catching on.  But, to be accurate, there has been, at least, one special significance given to the name “Blood Moon.”  Two Christian Pastors have pointed to a biblical prophecy in which the appearance of a series of blood-red moons signals the end of time.  

See: Four Blood Moons: Something Is about to Change

M Grossmann of Hazelwood, Missouri
(& Belleville, Illinois)
24 April 2014
About the Author

What are the “Moon’s Phases”?

26 June 2014

The Short Answer (TSA)

            The “Moon’s Phases” are the shapes of the sunlit part of the Moon’s face as seen in the night sky.  I say shapes because there are a number of different shapes taken by the sunlit part of the Moon’s face during the regular cycle of phases.  We pass through a full cycle of phases about every 29.6 days.

The Moon's Phases (Northern Hemisphere)

            The cycle of Moon’s phases begins with the “New Moon,” a time when the Moon can’t be seen at all in the night sky.  Of course, the Moon is still there, but to a person watching the sky from the Earth, no part of the face of Moon is reflecting any of the Sun’s light during the New Moon. 

            After the “New Moon” phase, the first visible reflected light appears on the Moon’s face as a tiny sliver in the shape of a crescent.  The Moon is a “Crescent Moon” as long as “some, but less than half,” of the Moon’s face is sunlit. 

            After the first light appears on the face of the Moon, the sunlit part of the Moon’s face continues to increase or get bigger.  When the size of the sunlit part of the face of the Moon is increasing, the Moon is called “waxing.”  So, that first “Crescent Moon” after the “New Moon” is called the “Waxing Crescent Moon.”     

            The “First Quarter” phase is reached when one half (1/2) of the Moon’s face is sunlit.  The name “quarter” causes some confusion. If half the Moon’s face is sunlit, why is it called a “quarter?”  In the name, “First Quarter,” the “quarter” refers to time instead of the shape of the sunlit part of the Moon’s face.  At the time of the “First Quarter” the Moon is one quarter of the way through one full cycle of phases. 

            When “more than half, but less than all” of the Moon’s face is sunlit, the phase is called a “Gibbous Moon.”  And, when the sunlit part of the Moon’s face is increasing toward a “Full Moon,” the phase is called the “Waxing Gibbous Moon.” 

            When the sunlit part of the Moon’s face increases until the whole face of the Moon is sunlit, we have “Full Moon.”  After the “Full Moon,” the sunlit part of the Moon’s face begins to get smaller.  This decreasing in size is called “waning.”

            After the “Full Moon” phase is over, “more than half, but less that all,” of the Moon’s face is sunlit.  So, again, we have a “Gibbous Moon” phase.  But during this “Gibbous Moon” the sunlit part of the Moon’s face is getting smaller instead of getting bigger.  So, this phase is called the “Waning Gibbous Moon.”

            When the sunlit part of the Moon’s face has decreased to the point that only one half (1/2) of the Moon’s face is sunlit, we have the “Third Quarter Phase.”  Again, “quarter” refers to time.  So, at the “Third Quarter,” the Moon is three quarters (3/4) through the complete cycle of phases. 

            When the sunlit part of the Moon’s face gets smaller than a half – so that “some, but less than half,” of the Moon’s face is sunlit, the “Crescent Moon” phase is back, again.  But, because the sunlit part of the Moon’s face is getting smaller, this is the “Waning Crescent Moon.” 

            The sunlit part of the Moon’s face continues to get smaller until the Moon seems to disappear
from the sky.  Then, the first phase, the “New Moon,” is back, again, and the cycle starts over.

            Before modern calendars, clocks and watches, the Moon’s phases were used to tell time.  The “Full Moon” phase got a number of colorful names depending on the season of that particular “Full Moon.”  The “Harvest Moon,” for example, is the “Full Moon” phase around the time farmers harvest crops in the fall of the year. 

            The “New Moon,” also got some colorful names because the Moon seems to disappear.  The “Dark Moon” refers to the “New Moon.”   And certain “New Moon’s” are called “Black Moon’s.”

            The “New Moon,” “First Quarter,” “Full Moon” and “Third Quarter” are often called the “major phases.”  The major phases are most often seen on modern calendars.

            The minor phases include the Waxing or Waning Crescent and Gibbous Moons. 

What is the Moon’s “Perigee”?

26 June 2014

The Short Answer (TSA)

            The “Perigee” is that point in the Moon’s orbit when it is closest to the Earth. The Moon’s orbit around the earth is not perfectly circular, but is more like an oval (or ellipse). So, sometimes, the Moon is closer or farther away from the Earth.

The Moon's Orbit around the Earth

When the Moon is closest to the Earth, at its “perigee,” the Moon appears significantly larger. If you compare photographs, it’s surprising just how much the distance of the Moon from the Earth can affect the Moon’s apparent size in the night sky.

Difference in Size in the Night Sky -- Apogee & Perigee

However, both the Moon’s apogee (farthest point from the earth) and perigee (closest point to the earth) have been precisely calculated for centuries. But why?

What makes the Moon’s distance from the Earth so important?

The “tides.”

Tides are the rise and fall of sea levels in coastal areas caused by the gravitational pull of both the Sun and Moon on the Earth’s oceans.  At its perigee, the Moon exerts significantly more gravitational pull on the oceans.

In coastal areas, the change in sea level between high-tide and low-tide is greater when the Moon is closer to the Earth.  So, if the Moon is at its perigee, the coastal water levels will drop more at low-tide, than when the Moon is farther away from the Earth.  In the same way, if the Moon is at its farthest point from the Earth, it’s “apogee,” the low-tides will not be as low as usual because the Moon is so far away from  the Earth that the Moon's gravitational pull on the oceans is less.

What is the “Apogee of the Moon”?

26 June 2014

The Short Answer (TSA)

            The “Apogee” is that point in the Moon’s orbit when it is farthest away from the Earth. The Moon’s orbit around the earth is not perfectly circular, but is more like an oval (or ellipse). So, sometimes, the Moon is closer or farther away from the Earth.

 The Moon's Orbit Around the Earth

             When the Moon is farthest from the Earth, at its apogee, the Moon appears significantly smaller in the sky. If you compare photographs, it’s surprising just how much the distance of the Moon from the Earth can affect the Moon’s apparent size in the night sky.

 Perigee & Apogee -- Change in the Moon's size in the Night Sky

              However, both the Moon’s apogee (farthest point from the earth) and perigee (closest point to the earth) have been precisely calculated for centuries. But why?

              What makes the Moon’s distance from the Earth so important?

              The “tides.” Tides are the rise and fall of sea levels in coastal areas caused by the gravitational pull of both the Sun and Moon on the Earth’s oceans.  At its apogee, the Moon exerts significantly less gravitational pull on the oceans.

               In coastal areas, the change in sea level between high tide and low tide is less when the Moon is farther away from the Earth.  So, if the Moon is at its apogee, there will still be a low tide, but the water level won’t drop as far as it does at other times. In the same way, if the Moon is at its closest point to the Earth, it’s “perigee,” the low tides will be significantly lower than usual because the the Moon is so close to the Earth that it’s gravitational pull on the oceans is greater.
 



 

What is a “Dead Moon”?

26 June 2014

The Short Answer (TSA)

            “Dead Moon” is a relatively unpleasant name for a particular phase of the Moon – the “New Moon.”  There are other names for the “New Moon” such as “Dark Moon.”  And certain “New Moons” are called “Black Moons.”  But you don’t, often, hear people use the word “dead” to describe a phase of the Moon anymore.  But, the name “Dead Moon” is an old one and, there is a logic to it.   

 The New Moon, The Dark Moon, or the Dead Moon

              In the regular cycle of the phases of the Moon, the “New Moon” is that part of the cycle in which the Moon disappears.  Or, at least, the reflected light of the Sun on the Moon’s face disappears completely from the night sky.  So, you look up in the sky at night and . . . no Moon.  

 

             It makes sense that this phase would get the name “Dark Moon."  And it, also, makes as much sense that some Dark Moons are called “Black Moons.” But what’s with “dead” Moon?

            Well, just before the “New Years” holiday, on January 1st of every year, we see some symbolic images – often of the old year depicted an old man and the new year as a baby.    Likewise, each cycle of the Moon’s phases used to be compared to the lifespan of a human being.  

             After the Full Moon, as the light reflected by the Moon’s face shrunk, the Moon was said to be getting older.  When the last light disappeared from the Moon’s face, the life of the Moon belonging to that cycle of phases was said to have “died.”  Then, after one and one-half (1 1/2) to three and one-half (3 1/2) days of darkness, the Moon would be “reborn” -- as the first sliver of reflected light appeared on its face in the night sky.     

What is a “Dark Moon”?

17 July 2014

The Short Answer (TSA)

            “Dark Moon” is another term for “New Moon.”  The “New Moon” is one of the regular phases of the Moon.  The "New Moon" phase is considered to be the end of the old cycle of phases as well as the beginning of the new cycle of phases.

The Dark Moon 

(Also the "New Moon")

            During phase called “New Moon,” the Moon is said to disappear from the night sky.  Well, the Moon, itself, doesn't disappear.   But, during the “New Moon,” none of the Sun’s light is reflected by the Moon's face.  So, the “New Moon” is also the “Dark Moon.” 

            At the “Dark (New) Moon,” all light vanishes from the face of the Moon for a period of one and a half to three and half days.  The "Dark Moon" (and New Moon) begins when the last sliver of reflected sunlight disappears from the outer edge of the face of the Moon.  And, the "Dark Moon" ends when the first sliver of reflected sunlight reappears on the outer edge of the face of the Moon.  With this first bit of reflected light, “Dark Moon” phase ends and the “Crescent Moon” phase begins.

Moon's Phases (Northern Hemisphere)

            Until the 20th Century, the Dark and New Moon were not always considered to be the same thing.  During the 19th Century, seafaring records called the last day, or days, of the “Old Crescent Moon” -- just before the last light disappears from the Moon’s face – the Dark Moon.  And, the first day, or days, of the “New Crescent Moon” – just after the first light reappears on the Moon’s face – was called the New Moon.

            To make things just a bit more confusing, there’s not only a “Dark Moon,” but something called “The Dark of the Moon.”  “The Dark of the Moon” is a period of 3 days before the “New (or Dark) Moon.”  “The Dark of the Moon” was long considered to be an unfavorable time to plant crops or to begin new projects.  “The Dark of the Moon” was included with the phases of the Moon in old farmers’ almanacs. 

What is a “Waning Crescent Moon”?

26 June 2014 

The Short Answer (TSA)

A Crescent Moon is one phase in the regular cycle of the phases of the Moon.  The Moon is in the “Crescent” phase whenever part, but less than half, of the Moon’s face is sunlit.  “Waning” means getting smaller.  So, the Moon is called a “Waning Crescent Moon” when the sunlit part of the face of the Moon is (1) getting smaller and (2) appears in the shape of crescent.

Waning Crescent Moon (Northern Hemisphere)

The Moon’s phases begin with the “New Moon” when the Moon disappears from the night sky.  The next phase is called the “Waxing Crescent Moon.”  The Moon reappears, but the sunlit part of its face is only a tiny sliver in shape of a crescent.  This first “Crescent Moon” continues to “wax” until it reaches the next phase, the “1st Quarter.”

Moon's Phases (Northern Hemisphere)

The “Waning Crescent Moon” comes at the end of the cycle of phases. The sunlit part of the Moon’s face “wanes” (or gets smaller) after the “Full Moon” until only half the Moon’s face is sunlit at the phase called the “3rd Quarter.”

As soon as less than one half (1/2) of the Moon’s face is sunlit, the “Waning Crescent Moon” begins. With each passing night the crescent of light gets smaller and smaller until all the light disappears at the next phase, the “New Moon.”  With the “New Moon” the cycle of phases begins again.

What is a “3rd Quarter Moon”?

26 June 2014

The Short Answer (TSA)

The “3rd Quarter” is one of the “major” phases of the Moon.  At the “3rd Quarter,” one half of the face of the Moon is sunlit.

3rd Quarter Moon (Northern Hemisphere)

The sunlit part of the “3rd Quarter” Moon’s face is “waning” (decreasing in size). After the “3rd Quarter,” the sunlit part of the Moon’s face continues to wane moving to the next phase, the “Waning Crescent Moon.” 

Moon's Phases (Northern Hemisphere)

During the “Crescent Moon,” some part, but less than half, of the Moon’s face is sunlit.  And, during the “Waning Crescent Moon,” the sunlit part of the Moon’s face is getting smaller and smaller – until the Moon (or at least the sunlit part of the face of the Moon) disappears completely from the night sky with the next phase, the “New Moon.”  At the “New Moon,” one cycle of the Moon’s phases ends and another begins.

The “quarter” part of the “3rd Quarter” phase name, sometimes, causes confusion.  If one half of the face of the Moon is sunlit, why is it called a “quarter” instead of a “half?”  But the term “quarter” refers to time – not the light on the face of the Moon.  So, the “3rd Quarter” is three quarters (3/4th) of the way through the full cycle of the Moon’s phases.

After the Moon disappears from the sky at the New Moon, the cycle begins again with the “Waxing Crescent Moon.”  The Moon will appear as a small sliver of light in the shape of a crescent in the night sky.  The sunlit part of the face of the Moon will be increasing or “waxing” during that first “Crescent Moon” after the “New Moon.” 

The sunlit part of the Moon’s face will continue to “wax” or increase until the whole face of the Moon is sunlit at the Full Moon.  Then, the Moon is said to “wane” as the sunlit part of its face decreases in size passing, again, through the “3rd Quarter” phase and, again, disappearing with the New Moon.

By the way, if you see a half moon in the sky, there’s a way to tell, at a glance, whether it’s the 1st or 3rd Quarter Moon.  I can say that, if the right side of the Moon is light and left side dark, it’s the “1st Quarter.”  If the left side of the Moon is light and right side is dark, it’s the “3rd Quarter.”  And, as long as you are in the Northern Hemisphere, this is a good “rule.”

But, if you live in Australia, South Africa, Chile, Argentina, or parts of Brazil, this rule is reversed.  So, if you live in the Southern Hemisphere, the left side of the Moon is light and right side is dark at the “1st Quarter.”  If the right side of the Moon is light and left side of the Moon is dark, it’s the “3rd Quarter.”

3rd Quarter Moon (Southern Hemisphere)

What is a “Waning Gibbous Moon”?

26 June 2014

The Short Answer (TSA)

 A Gibbous Moon is one phase in the regular cycle of the Moon's phases.  The Moon is “Gibbous” when more than half, but less that all, of the Moon’s face is sunlit.

Waning Gibbous Moon (Northern Hemisphere)

“Waning” means getting smaller.  So, the Moon is called a “Waning Gibbous Moon” when the sunlit part of the face of the Moon is (1) getting smaller in size, but still (2) covers more than half, but less than all, of the face of the Moon.  The “Waning Gibbous Moon” is the second “Gibbous Moon” in the regular cycle of phases. 

Moon's Phases (Northern Hemisphere)

The Moon’s phases begin with the "New Moon" -- when the Moon disappears and can’t be seen in the night sky.  When the Moon “returns,” it first appears as a “Crescent Moon” with the smallest sliver of light on its face.  

This “Crescent Moon” is called the “Waxing Crescent Moon” because the sunlit part of the Moon’s face is getting bigger.  And “waxing” means getting bigger.  The light on the Moon’s face continues to increase, or “wax,” until it reaches the “1st Quarter” phase when half the Moon’s face is sunlit.

The sunlit part of the Moon’s face continues to get bigger.  After the “1st Quarter Moon,” more than half, but less than all, of the Moon’s face is sunlit.  So, this is a “Gibbous Moon.”  But during this “first” “Gibbous Moon” phase, the sunlit part of the Moon’s face is getting bigger, or “waxing.  So, this phase is called the “Waxing Gibbous Moon.”

The sunlit part of the Moon’s face will continue to increase until the whole face of the Moon is sunlit.  Then, the Moon will have passed from the “Waxing Gibbous” phase to the next phase, the “Full Moon.”

But right after the “Full Moon,” the sunlit part of the Moon’s face begins to get smaller – “Wane.”  And, again, more than half, but less than all, of the Moon’s face is sunlit.  So, the Moon is Gibbous again.  But, now, the sunlit part of the Moon’s face is getting smaller every night. So, this second “Gibbous Moon” is the “Waning Gibbous Moon.”

The sunlit part of the Moon’s face will continue to get smaller until it reaches the next phase:  the “3rd Quarter” when only half of the Moon’s face is sunlit. 

But, before we go any father, we need to clear up some confusion of about the “quarter” Moons. At the phases called the “1st Quarter” and the “3rd Quarter,” exactly half of the Moon’s face is sunlit.  So, if one half of the Moon’s face is light, why is the phase called a “quarter?”  

“Quarter” refers to time instead of to the light on the Moon’s face.  So, the “3st Quarter” is three-fourths (3/4th) of the way through the time (29.6 days) it takes to complete a full cycle of the Moon’s phases: from the New Moon to the next New Moon.

After the “3rd Quarter,” the Moon "wanes" to the next phase, the “Waning Crescent Moon.”  When the sunlight disappears completely from the Moon’s face, we have a New Moon, and the cycle begins again.  

What is a “Waning Moon”?

9 July 2014

The Short Answer (TSA)

“Waning” means to get smaller.  So, when the Moon is said to be “waning,” it means that the sunlit part of the Moon's face is getting smaller.  The changes in the size of the sunlit area of the face of the Moon are called “phases.”  The Moon goes through a complete cycle of “phases” every 29.6 days.

Moon's Phases (Northern Hemisphere)

The cycle of phases begins with the New Moon, a time when the Moon cannot be seen in the night sky at all.  After the Moon disappears, it reappears as a crescent – a small sliver of light on the right outer edge of the face of the Moon.  With each night, the sunlit part of Moon will increase in size until the face of the Moon is completely sunlit – the “Full Moon” phase.

During the time from the New to the Full Moon, the Moon is said to “waxing.”  Waxing means to get bigger.   But, right after the Full Moon, the sunlit part of the Moon’s face begins to “wane” getting smaller and smaller.

Waning Moon

Even if you don’t know or remember when the Moon was “New” or “Full,” you can still tell whether or not the Moon is “waxing” or “waning.”  If the right outer edge of the Moon is sunlit, it is waxing.  If the left outer edge of the Moon is sunlit, it is waning.

Waxing (with right outer edge sunlit) to Full, then, Waning (with left outer edge sunlit)

But there’s a catch.  If you live in the Southern Hemisphere, Australia, Chile, Brazil, Argentina, or South Africa, the right-left rule is reversed.  So, in the Southern Hemisphere, if the left outer edge of the Moon is sunlit, it is waxing.  If the right outer edge of the Moon is sunlit, it is waning.

M Grossmann of Hazelwood, Missouri
(& Belleville, Illinois)
About the Author

Thursday 9 July 2014

What is a “Lunar Eclipse”?

19 June 2014

The Short Answer (TSA)

Lunar Eclipse

            The word eclipse comes from an ancient Greek word meaning "the darkening of a heavenly body."  For there to be a lunar eclipse, two things must happen.  First, the Earth must move in between the Sun and the Moon.  Second, the Moon must move exactly into the shadow cast by the Earth.

Lunar Eclipse Diagram

            Lunar eclipses don’t happen that often, but why not?  The Earth moves in between the Sun and Moon every month.  In fact, the Full Moon is the exact moment when the earth is in between the Sun and the Moon.  But only rarely is there a lunar eclipse with the full moon.

            There are two reasons.  First, the Earth casts a very small shadow and the Moon is a very small target.  Second, the orbit of the Earth around the Sun and the Moon’s own orbit around the Earth are not all on exactly a level plane.  So, most often, the Earth is a bit above or below the “level” of the Sun -- and/or -- the Moon is a bit above or below the level of the Sun and Earth. 

            Again, the Earth casts such a small shadow and the Moon is such a small target.  During most Full Moons, the shadow of the Earth will “miss” and pass just above or below the Moon.  So, most often, all we see is the full sunlit face of the Moon.

            But, once in a while, the Earth, and Moon will line up on exactly the same level plane.  When that happens, a sky watcher will see a Lunar Eclipse.  The Full Moon is suddenly darkens as a shadow moves across the face of the Moon until the whole Moon is completely covered by a dark shadow.

 

            But if you look carefully, you’ll notice that you can still see the faint outline of the darkened Moon.  It has a very dark reddish color.  From beginning to end, a Lunar  Eclipse will last about 1 hour and 45 minutes.

Video: Lunar Eclipse -- Described and Illustrated

What is a “Full Moon”?

25 June 2014

The Short Answer (TSA)

            The Full Moon is that time in the lunar cycle when the Moon’s face is entirely sunlit.  At the Full Moon, the full round face of the Moon is visible in the night sky.

  Full Moon

            In astronomy, a “Full Moon” happens when the Moon reaches that place in its orbit in which it is farthest from the Sun.  The Full Moon is also the time when the Earth passes between the Sun and the Moon.  Put yet another way, at the Full Moon, the Sun and Moon are “facing” each other with the Earth in the middle.

            Although the Earth is, “more or less,” in between the Sun and the Moon during the Full Moon, very, very rarely does the Earth pass exactly in between the positions of the Sun and Moon.  So, if you were standing on the Moon, during most Full Moons, the Earth and the Sun would appear to pass by each other, with the Earth passing just over or under the Sun.  So, during a typical Full Moon, we might say that the Earth misses the Sun’s as it passes by.

            But, on those rare Full Moons when the Earth actually passes directly in front of the Sun, there is a Lunar Eclipse.  During a Lunar Eclipse, the face of the Full Moon suddenly becomes dark as the Earth passes in front of the Sun and casts a shadow that passes across the face of the Full Moon.  Lunar Eclipses can only happen at the moment of the Full Moon.     

            The term “Full Moon” also describes a formal “phase” of the Moon.  The “phase of the moon” is the shape of the sunlit part of the Moon as seen from Earth.   That shape changes as the Moon goes through a full cycle of phases.  Each full cycle of the Moon’s phases takes about 29.6 days.  The phases of the Moon you hear the most about are the “1st Quarter,” “Full Moon,” “3rd Quarter,” and “New Moon.”

            But, let’s pause for a moment.  We need to clear up some confusion of about the “quarter” Moons. At the phases called the “1st Quarter” and the “3rd Quarter,” exactly one half of the Moon’s face is sunlit.  So, if half the Moon’s face is sunlit, why is it called a “quarter?”  

            The word “quarter” refers to time instead of to the light on the Moon’s face.  So, the “1st Quarter” is one fourth (1/4th) of the way through the time (29.6 days) it takes to complete a full cycle of the Moon’s phases: from the New Moon to the next New Moon.

            There are other “minor” phases, as well, including the “Crescent Moon” and “Gibbous Moon.”  When the sunlit part of the Moon’s face is getting larger, the Moon is said to be “waxing.”  And, when the sunlit part of the Moon’s face is getting smaller, the Moon is said to be “waning.” 

Lunar Phases (Northern Hemisphere)

            Before our modern clocks and calendars, the Moon’s phases were used to tell time.  The bright Full Moons of different months and seasons were, sometimes, given special names like “Harvest Moon” – the Full Moon closest to the beginning of autumn.  

What is a “Waxing Gibbous Moon”?

25 June 2014

The Short Answer (TSA)

            A Gibbous Moon is one phase in the regular cycle of phases of the Moon.  The Moon is “Gibbous” when more than half, but less that all, of the Moon’s face is sunlit.

Waxing Gibbous Moon

“Waxing” means increasing.  So, the Moon is called a “Waxing Gibbous Moon” when the sunlit part of the face of the Moon is (1) increasing in size and (2) covers more than half, but less than all, of the face of the Moon

Moon's Phases (Northern Hemisphere)

The Moon’s phases begin with the "New Moon" -- when the Moon disappears and can’t be seen in the night sky.  When the Moon “returns,” it first appears as a “Crescent Moon” with the smallest sliver of light on its face.  The light on the Moon’s face increases until it reaches the “1st Quarter” phase when half the Moon’s face is sunlit.

But, before we go any father, we need to clear up some confusion of about the “quarter” Moons. At the phases called the “1st Quarter” and the “3rd Quarter,” exactly half of the Moon’s face is sunlit.  So, if half the Moon is light, why is it called a “quarter?”  

The word “quarter” refers to time instead of to the light on the Moon’s face.  So, the “1st

Quarter” is one fourth (1/4th) of the way through the time (29.6 days) it takes to complete a full cycle of the Moon’s phases: from the New Moon to the next New Moon.

After the “1st Quarter Moon,” the Moon is called “Gibbous.” Again, this means that more than half, but less than all, of the Moon’s face is sunlit.  Because the sunlit part of the Moon’s face is increasing in size, this is not just the Gibbous Moon, but the “Waxing Gibbous Moon.”

The sunlit part of the Moon’s face will continue to increase until the whole face of the Moon is sunlit.  Then, the Moon will have passed from the “Waxing Gibbous” phase to the next phase, the “Full Moon.” 

What is a “Gibbous Moon”?

19 June 2014

The Short Answer (TSA)

Most have heard of the “Crescent Moon,” and most of us know what a crescent shape looks like.  But a “Gibbous Moon” doesn't ring any familiar bells. The Moon is “Gibbous” when more than half, but less that all, of the Moon’s face is sunlit.

1st Quarter (left), Gibbous Moon (center), and Full Moon (right) 

The Moon’s phases begin with the "New Moon" -- when the Moon disappears and can’t be seen in the night sky.  When the Moon “returns,” it first appears as a “Crescent Moon” with the smallest sliver of light on its face.  The light on the Moon’s face increases until it reaches the “1st Quarter” phase when half the Moon’s face is sunlit.

But, before we go any father, we need to clear up some confusion of about the “quarter” Moons. At the phases called the “1st Quarter” and the “3rd Quarter,” exactly half of the Moon’s face is sunlit.  So, if half the Moon is light, why is it called a “quarter?”  

The word “quarter” refers to time instead of to the light on the Moon’s face.  So, the “1st Quarter” is one fourth (1/4th) of the way through the time (29.6 days) it takes to complete a full cycle of the Moon’s phases: from the New Moon to the next New Moon.

After the “1st Quarter Moon,” the Moon is called “Gibbous.” Again, this means that more than half, but less than all, of the Moon’s face is sunlit.  There are two “Gibbous Moons” in each cycle of the Moon’s phases. 

The first is called the “Waxing Gibbous Moon.”  “Waxing” means increasing.   So, the “Waxing Gibbous Moon” is the phase between the “1st Quarter Moon” and the “Full Moon,” when the sunlit part of the Moon’s face is increasing in size.  

There will be another Gibbous Moon.  But the next one will be called a “Waning Gibbous Moon.”  “Waning” means decreasing.  The whole face of the Moon is sunlit at the Full Moon but, then, the sunlit part of the Moon’s face begins to decrease in size.

Just after the Full Moon, we have another Gibbous Moon because, again, more than half, but less than all, of the Moon’s face is sunlit.  But the sunlit part of the Moon’s face will continue to decrease.  So this is a “Waning Gibbous Moon.”  The “Gibbous” phase will end when only half of the Moon’s face is sunlit, the “3rd Quarter Moon.”

M Grossmann of Hazelwood, Missouri
(& Belleville, Illinois)
About the Author
19 June 2014