“No matter what phase the Moon is in, one thing is the same: half of the Moon is illuminated by the sun. What changes from night to night is how much of that half we can see from Earth. When the entire illuminated half of the Moon is facing Earth, we see a full circle of light, which we call a full moon. Then, as the Moon continues in its orbit around Earth, we see less and less of it until the illuminated half is facing directly away from Earth, and it seems to disappear. This happens when the illuminated half faces entirely away from Earth, and we call this a new moon. But don’t worry-the Moon is never out of sight for very long. As its orbit around Earth continues, the illuminated half of the Moon moves back into our view-just a little at first, but more and more each night until, about a month after the last full moon, it is finally full again.”