Moon phases are the phases the moon goes through on its orbit of the Earth. They range from a white circle to a thin sliver of light like crescent they are nacture giants
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A regular moon, it even has phases
Since the sun illuminates the moon, no moon phases can be seen from the sun, all moons and planets always are 'full'.
This is a good link to see the moon phases. (See below) It will look like a sliver.
The moon's phases look the way they do because it takes one monthe for the moon to rotate around the Earth. You can only see certain parts of the moon because the light of the sun shines only on the part of the moon not covered by the Earth.
It would be a lunar calendar. That means the calendar would not be based on the phases of the sun (or day), but on the phases of the moon.
Venus has phases like the moon
look in the link below.
Venus
the moon and the sun and the earth all make the moon look different because of shadows
The moon has different phases that it passes through, just like we have different phases in our lifetimes.
mercury
Venus