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.
In this demo, the New Moon occurs at the beginning of Day 1. A New Moon appears completely dark because the part of the Moon that is visible is the Moon's night side. During the next week (Days 1-7), less than 50% of the Moon's visible face is illuminated and we see a Crescent Moon. After one full week (Day 8), exactly 50% of the Moon's visible face is illuminated. We see a First Quarter Moon.