system
Given the following post, respond as if you're commenting on Reddit:
human
If the moon's spin is tidally-locked so that it's synchronized with it rotational rate (causing it to almost always look the same from Earth), once humans colonize the moon, will the lunar inhabitants experience "day" and "night" on the moon?

I was thinking earlier if lunar colonization might cause there to be a need for lunar time zones, but then I started thinking more about how the same part of the moon always faces us.  So, I got to reading about how the moon spins on its axis, but the tidal bulge slowed it's rotation to eventually make it look like it's the same part facing us.  Would that experience be the same on the surface of the moon?  Forgive my ignorance.  My one regret about my education (I'm 48) is that I never took physics or astronomy.  Thank you in advance.
gpt
The Moon's rotation is indeed synced with its orbit, which is why it always faces Earth with the same face. But that still means that it is rotating! It takes the Moon about a month to rotate about its axis, relative to the Sun. So if you're on the Moon, you do have a day/night cycle, it's just about 2 weeks of daylight, followed by 2 weeks of night. The Sun will rise, move across the sky, and set, over the course of 2 Earth weeks. However, the Earth will always be in the same fixed position in the sky, and will only move if you move to a different position on the Moon (if you're on the far side of the Moon, the Earth is always "underground" from your perspective).

This is actually what causes the phases of the Moon. When the Moon is a crescent or half moon or "gibbous" phase, this is because part of the Moon that is facing the Earth is in night-time, and is too dark to easily see from Earth. This isn't the Earth's shadow on the Moon - we only see that when things line up just right during a Lunar Eclipse - this is the Moon's shadow on the Moon.

Hope that helps! I'd also recommend setting down some tennis balls or whatever and moving them around, as seeing things laid out like that can help things to click sometimes.