What is the origin of 'sleep tight'? One of the mysteries of the English language finally explained.
The moon doesn't glow in a very real sense. It reflects the Sun's light. (Or the Earth's light if you're not on Earth and in the right position.) As Quora User says, the moon has a high albedo. So it reflects pretty well.
The animation moves fast, but you can see that the moon has half its surface lit by the sun. As the moon circles the Earth each month, it presents different amounts of that sunlit side to the Earth. Most of the time, some of the sunlit side of the moon will not be in our view.