Whois & Analysis for moongiant.com

The lunar phase or phase of the moon is the shape of the illuminated (sunlit) portion of the Moon as seen by an observer on Earth.

The lunar phases change cyclically as the Moon orbits the Earth, according to the changing positions of the Moon and Sun relative to the Earth.

The Moon's rotation is tidally locked by the Earth's gravity, therefore the same lunar surface always faces Earth.

This face is variously sunlit depending on the position of the Moon in its orbit.

Therefore, the portion of this hemisphere that is visible to an observer on Earth can vary from about 100% (full moon) to 0% (new moon).

The lunar terminator is the boundary between the illuminated and darkened hemispheres.

Each of the four "intermediate" lunar phases (see below) is roughly seven days (~7.4 days) but this varies slightly due to the elliptical shape of the Moon's orbit.

Aside from some craters near the lunar poles such as Shoemaker, all parts of the Moon see around 14.77 days of sunlight, followed by 14.77 days of "night".

(The side of the Moon facing away from the Earth is sometimes called the "dark side of the Moon", although that is a misnomer).

A full moon is the lunar phase that occurs when the Moon is completely illuminated as seen from Earth.

This occurs when Earth is located directly between the Sun and the Moon (more exactly, when the ecliptic longitudes of the Sun and Moon differ by 180 degrees).

This means that the hemisphere of the Moon that is facing Earth (the near side) is almost fully illuminated by the Sun and appears round (while the far side is almost completely unilluminated).

On some occasions at the time of full moon there is also a lunar eclipse so the moon's face appears reddish due to the rayleigh scattering of blue light in Earth's atmosphere.

A month is a unit of time, used with calendars, which is approximately as long as a natural period related to the motion of the Moon; month and Moon are cognates.

The traditional concept arose with the cycle of moon phases; such months (lunations) are synodic months and last approximately 29.53 days.

From excavated tally sticks, researchers have deduced that people counted days in relation to the Moon's phases as early as the Paleolithic age.

Synodic months, based on the Moon's orbital period with respect to the Earth-Sun line, are still the basis of many calendars today, and are used to divide the year.