How often does a full moon occur and why?

Question

How often does a full moon occur and why?

Answer 1

Full moons happen approximately once every 28 days or so.

When the moon is in view, quite often, the sun will be on the other side of the earth, therefore casting a shadow onto the moon, causing it to not be visible. When the moon moves around the earth, different portions of the moon will be visible, causing different 'stages' such as waning gibbous and waxing gibbous.

When no shadow is projected onto the moon, it is called full.

Answer 2

Full moon is a lunar phase that occurs when the Moon is on the opposite side of the Earth from the Sun. A full moon occurs when the Moon is in opposition with the Sun. At this time the hemisphere of the Moon that is facing the earth (the near side) is fully illuminated by the Sun and appears round. Only during a full moon is the opposite hemisphere of the Moon, which is not visible from Earth (the far side), completely unilluminated.

In any event, the period between full moons can be either 29 or 30 days.

Answer 3

A full moon occurs... once every 29 days or so.

It occurs with every moon cycle.

Sometimes....though very seldom....you may get 2 full moons within one month....this is called a "Blue Moon".

Answer 4

Once a month.  It has to do with the orbit of the moon and the orbit of the earth.

Answer 5

Every month. Or more exactly every 27,3 days, because that's how long it takes for the moon to orbit around the earth. The moon has to be on the other side of the sun.

Hmm I wish I could draw a picture to explain..

Ah here we go.. I found one which explains it

http://www.emporia.edu/earthsci/amber/st...

Answer 6

Moon goes round the earth once in 27days 8hours.But during this time erth is not stand still.It is moving round the sun.So it takes about 29days from Full moon to full moon. Inorder to come to same posoition as full moon,Moon has to catch up with the moving earth.

Answer 7

It occurs every 28 or 29 days

thats how long the cycle is...

usually once a month...

rarely twice a month...

Answer 8

About every 29 days, it's due to the moon's orbit around the earth, as well as the earth's orbit around the sun.  If you just look at the moon's orbit around the earth, it takes ~27 days, but because the earth ALSO is moving in its orbit around the sun, it actually adds a little more time for the same phase to appear from our perspective.