The moon doesn't actually have a "dark" half. It's the angle of sunlight hitting the moon's surface that creates the illusion of a dark half. Here's why:

* The moon reflects sunlight: The moon doesn't produce its own light. It reflects sunlight, just like a mirror.

* The sun's perspective: The sun illuminates half of the moon's surface at any given time.

* Earth's perspective: As the moon orbits the Earth, our perspective on the sunlit portion changes. This is why we see different moon phases.

Here's a simplified explanation:

1. New Moon: The moon is between the sun and the Earth. The sunlit side faces away from us, so we see the moon as dark.

2. Waxing Crescent: The sunlit part of the moon starts to become visible from our perspective, appearing as a thin crescent.

3. First Quarter: We see half of the sunlit side of the moon, which looks like a quarter-circle.

4. Waxing Gibbous: The sunlit area continues to grow, becoming more than half illuminated.

5. Full Moon: The moon is opposite the sun in the sky, with the entire sunlit side facing us.

6. Waning Gibbous: The sunlit area starts to shrink, becoming less than half illuminated.

7. Last Quarter: We see half of the sunlit side again, but this time it appears like a quarter-circle facing the opposite way from the first quarter.

8. Waning Crescent: The sunlit part continues to shrink, leaving a thin crescent before returning to the new moon phase.

The "dark" half is actually the side of the moon that's not illuminated by the sun at that particular time. It's not always the same half of the moon, but rather depends on the moon's position relative to the sun and Earth.