Skies of Change: Observing Phases of the Moon

Full Moon

Full Moon

My dogs and I spend many hours outside.  We often get up early to see the first rays of sun at dawn.  In the stillness, we sometimes see the moon as well, fading with each passing moment as the sun becomes stronger.

We also enjoy watching the sunset in the west changing color as the shadows of night start to fall.  Looking over to the east, we can see the moon rising above the woods behind our back field.  This week, we have watched the moon grow fuller and brighter.  It will continue to do so until April 4, which is the date of the full moon this month.

Names of the April Full Moon

Many years ago, I read an article in the paper about the names given to each full moon.  I can remember some of the names like the Harvest moon and Hunter’s moon because they are in folklore and stories.  However, I could not remember the name for April’s full moon, so the dogs helped me do some research.

Moss pink

Moss pink

The Native Americans gave each month’s full moon distinctive names to help them keep track of the seasons.  Different tribes used different names depending upon their location.  The Algonquin tribes called the full moon of April the Pink Moon, Sprouting Grass Moon, or Egg Moon.  The Pink Moon referenced the early widespread flowers of the herb moss pink, or wild ground phlox.  Coastal tribes called it the Fish Moon because it coincided with the shad swimming upstream to spawn.

Moon Phases

For years, my dogs and I have noticed the changing shape of the moon each night.  We enjoy the fuller moons because they give us light to see even in the dark.  We’ve also come to enjoy the crescent moons because they are so crisp hanging in the sky.  What causes the changing shapes of the moon?

Changing angles of the earth, moon, and sun cause the moon to have phases, or appear different, as it orbits the earth.  There are eight different moon phases.  After my dogs and I watch the full moon on April 4, we will see the following moons:

  • Waning gibbous
  • Third quarter
  • Waning crescent
  • New moon
  • Waxing crescent
  • First quarter
  • Waxing gibbous

Half of the moon’s face is always lit by the sun.  However, we do not always see the side of the moon’s face that is lit because of the position of the moon in its orbit relative to the earth.  During a full moon, the earth, moon, and sun are aligned, and we can see the entire side of the moon that is lit.  During a new moon, the earth, moon, and sun are also aligned, but the moon is between the sun and the earth, so we do not see the side of the moon that is lit by the sun.

Waning vs Waxing

What’s the difference between waning and waxing? A waning moon appears to shrink each night until reaching the new moon stage.  A waxing moon continues to grow each night until reaching the full moon stage.  To remember the difference between waning and waxing, think of the capital letters C and D.  A waning moon looks like a C, and a waxing moon looks like a D.

Gibbous vs Crescent

One of the many moons we have watched at sunset

One of the many moons we have watched at sunset

What do gibbous and crescent describe? Gibbous moons are more than half full, but less than full.  Crescent moons are less than half full, but fuller than the new moon.  Gibbous is Latin for humpbacked.  Crescent is derived from the Latin crescens, meaning to grow.

Quarter Moons

The quarter moon gets its name from the fact that it is one quarter of the way around the earth in the orbit cycle. First quarter moons rise at noon and are at the apex of the rise at sunset.  They set, or disappear from view, at sunset.  Last (or third) quarter moons rise around midnight and reach their apex at sunrise.  They set at noon.

Orbit Time

So how much time does it take for the moon to go through all eight phases before starting over again? The moon takes approximately 27 days to orbit the earth.  This means that the phases of the moon take about 27 days to complete before starting over again.

Though we will have to wait to see another full moon, we can enjoy the other moon phases in the interim, along with the spring-like weather that has arrived in our area.

Resources and Related Links

First quarter moon – http://earthsky.org/moon-phases/first-quarter

Full moon – http://earthsky.org/moon-phases/full-moon

Gibbous moon – http://www.universetoday.com/20324/gibbous-moon/

Last (or third) quarter moon – http://earthsky.org/moon-phases/last-quarter

Native American full moon names – http://farmersalmanac.com/full-moon-names/

Moon orbit time – http://www.space.com/24871-does-the-moon-rotate.html

Moon phases – http://www.moonconnection.com/moon_phases.phtml

Moss pink – http://www.britannica.com/EBchecked/topic/456994/phlox

Shad – http://www.fws.gov/chesapeakebay/shad.htm

Waning and waxing moons – http://www.differencebetween.net/science/nature/difference-between-waxing-and-waning/

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