Babylonian sky records
Does the sky repeat itself?
That time, that place
Babylonian kings wanted to know what was coming for their kingdom. That job fell to the priests, who believed events in the sky foretold events on Earth. So night after night, they watched.
Why this question
The belief was wrong, but the method was serious. A prophecy is only as good as the observation behind it. So the priests recorded, night after night, what appeared where — and the records piled up over centuries.
What was found
As the records accumulated, something unexpected emerged: the sky was repeating itself. Venus appeared and vanished in a fixed sequence; eclipses returned in similar form roughly every 18 years. What they took for divine whim had a rule inside it. Data gathered to prophesy revealed instead that things could be predicted.
The sky is the will of gods, unknowable to humans
Clay tablets holding centuries of observations
These records passed to Greece and became the basis of later astronomical calculation