Moon Phases

Full Moon - New Moon - Waxing/Waning Moon

Which way are we spinning around the sun? counterclockwise!

All the planets and most of the other objects in the solar system circle the sun

Earth is 8 light minutes from the sun

The sun is eight light minutes from Earth, and Pluto is 12 light hours away. 1 Or in English it takes light 8 minutes to get from the sun to Earth and 12 hours for light to get from the sun to Pluto.

Full Moon - New Moon - Waxing/Waning Moon

I think Wax means to grow or get bigger.

And I think Wane means to shrink or get smaller.

I think a New Moon is a Dark Full Moon.

I think a New Moon is called a New Moon because the old moon disappears and becomes black and a New Moon arises out of the old Moon.

Enought of my thinking so read on.


When the sun and moon are on opposite sides of the earth, the moon appears "full" to us, a bright, round disk.

When the moon is Full, the Moon and the Sun rise and set at about the same time. (from the next article)

When the moon is between the earth and the sun, it appears dark, a "new" moon.

When the moon is New, the Moon and the Sun rise and set at about the same time. just like when the Moon is Full (from the next article)

I wrote this. We cant see the moon at this point! We can only see the shadow of the moon! See the 2nd article or web page!

In between, the moon's illuminated surface appears to grow (wax) to full, then decreases (wanes) to the next new moon.

The edge of the shadow (the terminator) is always curved, being an oblique view of a circle, giving the moon its familiar crescent shape. Because the "horns" of the moon at the ends of the crescent are always facing away from the setting or rising sun, they always point upward in the sky. It is fun to watch for paintings and pictures which show an "impossible moon" with the horns pointed downwards.


Moon Phases Simplified

the new moon occurs when the moon is positioned between the earth and sun. The three objects are in approximate alignment (why "approximate" is explained below). The entire illuminated portion of the moon is on the back side of the moon, the half that we cannot see.

At a full moon, the earth, moon, and sun are in approximate alignment, just as the new moon, but the moon is on the opposite side of the earth, so the entire sunlit part of the moon is facing us.

The first quarter and third quarter moons (both often called a "half moon"), happen when the moon is at a 90 degree angle with respect to the earth and sun. So we are seeing exactly half of the moon illuminated and half in shadow.


An easy way to remember and understand those "between" lunar phase names is by breaking out and defining 4 words: crescent, gibbous, waxing, and waning.

The word crescent refers to the phases where the moon is less that half illuminated.

The word gibbous refers to phases where the moon is more than half illuminated.

Waxing essentially means "growing" or expanding in illumination,

and waning means "shrinking" or decreasing in illumination.

Thus you can simply combine the two words to create the phase name, as follows:

After the new moon, the sunlit portion is increasing, but less than half, so it is waxing crescent.

After the first quarter, the sunlit portion is still increasing, but now it is more than half, so it is waxing gibbous.

After the full moon (maximum illumination), the light continually decreases. So the waning gibbous phase occurs next.

Following the third quarter is the waning crescent, which wanes until the light is completely gone -- a new moon.


Moonrise from Earth:

The moon rises and sets every day. The time depends on the phase of the moon.

It rises about 30 to 70 minutes later each day than the previous day

At the time of the new moon, the moon rises at about the same time the sun rises, and it sets at about the same time the sun sets.

As the days go by (as it waxes to become a crescent moon, a half moon, and a gibbous moon, on the way to a full moon), the moon rises during daytime (after the sun rises), rising later each day, and it sets at nighttime, setting later and later each night.

At the full moon, the times of moonrise and moonset have advanced so that the moon rises about the same time the sun sets, and the moon sets at about the same time the sun rises.

As the moon wanes (becoming a half moon and a crescent moon, on the way to a new moon), the moon rises during the night, after sunset, rising later each night. It then sets in the daytime, after the sun rises.

Eventually, the moon rises so late at night that it's actually rising around sunrise, and it's setting around sunset. That's when it's a new moon once again.


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