The Moon is tidally locked to the Earth, meaning that one side always faces us (the nearside), whereas the farside is forever hidden from us. In addition, the Moon is illuminated on one side by the Sun, the other side is dark (night).

Which parts are illuminated (daytime) and which parts we see from the Earth are determined by the Moon's orbit around the Earth, what is called the phase of the Moon (click here for the current phase of the Moon).
As the Moon moves counterclockwise around the Earth, the daylight side becomes more and more visible (i.e. we say the Moon is `waxing'). After full Moon is reached we begi n to see more and more of the nighttime side (i.e. we say the Moon is `waning'). This whole monthly sequence is called the phases of the Moon.

Eclipses:
On rare occasions the Moon comes between the Earth and the Sun (a solar eclipse) or the Moon enters the Earth's shadow (a lunar eclipse).



All solar eclipses occur at new moon with a duration of only 4 to 7 mins. The path of shadow across surface of the Earth determines who gets to see it.
