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Name: Sally
Status: Other
Age: 50s
Location: N/A
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Date: N/A 

I have been looking for the answer to this question everywhere and cannot find it. Who discovered that the earth was on a 23.5 degree tilt and when was it accepted?

I don't know who is credited with determining that the Earth is tilted, but scientific observers/astronomers surely knew it by the time of the invention of the telescope. The effects of the tilt were apparent even to the ancients, by 2000 BC, as they were building pyramids and astrological devices (stone circles, etc.) to allow them to track the seasons. Eventually Milutin Milankovitch used the tilt and the variation of it with time, plus the Earth's orbit around the Sun to help explain long term climate changes.

David Cook

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