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How did the ancient cultures determine that the year was actually a fraction of an extra day beyond 365 days?

This is not so hard to do. All you really need is a bit of care, a few sticks and a convenient place to observe the sunrise or sunset. So note that there is a cycle of the year and you want to know ...
James K's user avatar
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25 votes

How did the ancient cultures determine that the year was actually a fraction of an extra day beyond 365 days?

It's easier than you think to notice the fraction... simply because the rounding error compounds over the years! After a good amount of years, you notice that solstices are drifting from their ...
Offirmo's user avatar
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18 votes

How did the ancient cultures determine that the year was actually a fraction of an extra day beyond 365 days?

The ancient Egyptians appeared to know that the year was 365.25 days. This was established by observing on what day the heliacal rising of Sirius occurred (i.e. on what day that it first becomes ...
ProfRob's user avatar
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11 votes

How did the ancient cultures determine that the year was actually a fraction of an extra day beyond 365 days?

For the most part, they didn't. Calendars have historically been a practical device. They were used to measure times of events, such as the planting and harvesting of crops. They only needed to be ...
Cort Ammon's user avatar
7 votes

How did the ancient cultures determine that the year was actually a fraction of an extra day beyond 365 days?

There is a good article in the Britannica. It seems the Sumerians used a 360-day year, and stuck an extra month in when the seasons got too far out of whack. The present year is a leap year(sic). The ...
Simon Crase's user avatar
3 votes

How did the ancient cultures determine that the year was actually a fraction of an extra day beyond 365 days?

How do you observe those Sunrises and sunsets are pretty obvious. However, in order to accurately measure the length of day versus night, you need a type of clock that's not a sundial. A water ...
dan04's user avatar
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3 votes

How did the ancient cultures determine that the year was actually a fraction of an extra day beyond 365 days?

Count the days. Many days. You cannot expect high accuracy if you measure the thickness of a single sheet of paper with a ruler. You can improve it greatly if you stack 1000 sheets, measure the total ...
Eric Duminil's user avatar
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1 vote

How did the ancient cultures determine that the year was actually a fraction of an extra day beyond 365 days?

For long-term consistent time measurements there would usually be markings put on the walls of irrigation canals which would cast a sharp shadow against the opposing wall of the stone-walled canal or ...
Amrita Bithi's user avatar

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