Why is it that we officially start a new day at midnight instead of at dawn?
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The nature of using a static 24 hour day means we must choose some exact time that the day starts and ends.
If we didn’t the time would be different for every single location on earth as dawn would occur at different times.
What if you’re in Alaska and its light or dark for 16 hours a day?
In old times, each city would have their own time and clock. That sucked. Our standardized system is far better.
Better question:
Why do we have 24 hours in a day and Americans insist they can only count to 12?
When is dawn, though? If I live a couple hundred miles north of you, even in the exact same longitude, my dawn will start at a different time to yours, but our midnights will still be the same time.
I was reading a Napoleonic war naval book, and about 1810 they start talking about someone toying to move it to midnight. Prior, the naval day began at noon, as measured by sextant.
Anywhere off the equator, the time dawn and dusk start changes a lot depending on the month.
What doesn’t change at all is midday.
The people who made clocks would figure out exactly the position a shadow would move to when the sun was at its highest.
That point is called Meridiem in latin.
Since they had a point they could always measure, they divided the day into “Before Meridiem” or “Ante Meridiem (AM)” in latin, and “After Meridiem” or “Post Meridiem (PM)” in latin.
And since Midday was now the middle of the day, it made sense that the opposite time was the start/end of the day.
Hence why the day begins at midnight.
Biggest issue with dawn is that each day would have a different length. Even if you just stay in one location. Dawn just makes it hard. It would also change when you move north/south. And some places don’t have dawn at times.
Starting with noon or midnight solved that problem. Noon is easy to measure, just put a vertical stick in the sand.
If you start at noon, then one activity period of humans is spread across two days. Midnight solves this problem.
After all this you still have to deal with longitude/time zones 🙂
If time is not exact, you can start the day whenever you want. Some cultures start the evening before. Christmas Eve is the night before Christmas for that reason.
Ethiopian time sets dawn/6AM as the start of the day (their 12:00). So it’s pretty confusing when you see business opening time of 0300… And they use a 12-hr cycle so 6PM is 12:00 again.
The only two consistent points in the day are when the sun is at its highest in the sky, and when it is at its lowest (the middle of the night – where you won’t be able to see it).
The other points of the day we can easily mark – sunrise and sunset) change throughout the year. At the equator they stay virtually the same year round, but the further north and south you go the more they will vary until you get so far north or south that there are entire periods of the year where the day is so long the sun wont set at all, or so short it will never rise.
So that means if you set 12 o’clock on the moment the sun rises, it would be different depending on how far north or south of the equator you were, and then vary some more based on which time zone you were in, and then vary some more again based on the season, and telling the time would be nearly impossible to track.
Because midnight and midday never move, they give us a nice consistent point to set our watches by, and setting the day to change at midnight is just a little more convenient as it happens when most people are asleep, rather than halfway through the day when everyone is working.
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