MNN Galleries

How much do you know about the moon?

The quarter moon setting over Boulder's Flatirons

Photo: Patrick Cullis/Flickr

4 of 12

Quarter moon

In the next step of the lunar cycle, the moon appears only halfway illuminated. Though it's commonly called a half moon because of its shape, the correct term "quarter moon" refers to its cycle around the Earth. Towards the beginning of the cycle, the phase is called "first quarter;" towards the end, it's called "third" or "last" quarter.