Why does the sun go down at different times in different places?
Asked by
mdlukas (
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November 18th, 2006
I am living in Turkey and have noticed that the sun sets much earlier here than in other places I've lived. Shouldn't time zones take care of that problem?
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11 Answers
I think it has to do with how far north and south you are. The time zone lines are drawn as if the earth were flat, but since it isn't, i suspect that would make a difference. I'm just guessing, but that seems to make the most sense to me. I know it get dark earlier in Seattle than in SF and we're in the same time zone.
It's actually quite complicated... First of all, within each timezone, it's going to fluctuate (as they are quite wide).
But occ is right about the Latitude, that is a huge factor (It some northern regions it can be night or day for 23 hours, depending on the season).
If you want to get precise (I worked at an outer space research lab at MIT and wrote the "Time Library"), there are lots of details. The earth's orbit, axis, and lots of geometry come into play. But mainly it's the latitude, timezone, and time of year.
Extreme changes in altitude can also make a difference.
And actually, in the summer, it is light in Seattle much later than in San Francisco. Maybe in the winter, it is a shorter day, but we could check.
The further away you get from the equator, the shorter the days are in the winter, and the longer they are in the summer. Which is why Seattle winters make me want to shoot myself.
Aside: Ben, you wrote the Time Library?
Don't forget the tilt (and perturbation) of the earth's axis to celestial equator and also that earth's orbit around sun is ellipse. When axis in N. hemisphere is tilted towards sun (our summer), earth is actually further away than it is in N. Hem. winter. Take a good Astronomy 101 course. Really fun.
bob: Yeah, lots of it. But that involved implementing long algorithms out of fat textbooks. And realizing time is a very tricky beast, esp. when you care about 100,000nths of a seconds.
Sunset is also affected by simple things like mountains. Sunset in Palm Springs comes earlier than Indio.
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