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Name: Brian F.
Status: student
Age: 14
Location: N/A
Country: N/A
Date: 12/10/2002
Question:
As winter approaches, why is the amount of daylight lost each day not the same?

Replies:
Think of the line that the Sun takes as a sine-wave, so the daily difference near the solstices (when the Sun is on a tropic) is nearly negligible, but at the equinoxes (when the Sun is at the equator) there is a very big daily difference. To complicate matters, the line isn't a perfect sine-wave, but is distorted due to the orbital motion of the Earth. This means that the earliest sunrise does not occur on the same day as the latest sunset. The differences are about two weeks for the northern summer solstices (June) and a three-weeks for the northern winter solstices (December). The greater difference in December is caused by the Earth's faster orbital motion at that time.

Howard Barnes.


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