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Name: Reginald
Status: other
Grade: other
Location: NV
Country: N/A
Date: N/A
Question:
Hello there, This question is regards to changes in sunrise/sunset times. I understand how they work, but surely the amounts by which the times differ on a day to day basis depend on the time of year. I would expect for the greatest change to be around March 21st and September 21st as they are the opposite days from the solstices. Does the rate of change of time depend on what rate the angle is changing between the earth's tilt and the sun?

Replies:
Dear Reginald.

You got that right! the greatest change in daily sunset and sunrise times is around the equinoxes each year. However the tilt angle changes from 22.1 to 24.1 over many thousands of years, very slowly indeed! For all practical purposes it is constant.

David H. Levy


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