Recently, I realized that days are very weird. Consider the current day. At the time of writing, it is December 8th at my time zone. And as you read this, there is a sweeping line on the dark side of the earth that we call "midnight" which is advancing little by little. In its wake, a new day starts.
East of the line, it's the 8th. West of the line, it's the 9th. That's what it means for midnight to pass. One day becomes another.
It's strange because of this: if one side of the midnight line is the 8th, and the other side is the 9th, then that means somewhere on the daytime side of the earth, the day changes back from the 9th to the 8th. Otherwise, we would not see the day increase at the midnight line.
It means that there is a daytime equivalent to the day change, but in reverse. The day ticks backwards. But where does this happen?
There's a line called "noon" or "midday" that sweeps across the bright side of the earth. It's the opposite twin of the "midnight line". However, you and I both know that the noon line does not make any change to the day number. Morning turns into evening and we are still on the same day. So, the noon line has no connection at all to the reverse ticking of the days.
How can the day reverse on the lit side of the planet? I encourage you to think about this and think of ways this could work. Click these clues to see them.
There has to be a line at which the day number reverses.
The noon line does nothing to the day number. This is true for all points on Earth's surface.
Think about time zones.
You can do your own research to find the solution. This was just something that disturbed me for a few weeks until I realized what was happening. And now that I know, I feel much better about the day number!