[According to this site](https://www.timeanddate.com/sun/usa/atlanta) between 1/1/24 – 1/31/24 sunset goes from 5:39-6:07, but sunrise goes from 7:42-7:35. Why does sunset change by 28 minutes, but sunrise only changes by 7?
In: Planetary Science
It’s because we use “mean” time, where every day (from 12:00 to 12:00 the next day) lasts exactly the same, mean (average) time. In reality, the sun moves at a variable speed, so the interval between the sun being highest in the sky (noon) on consecutive days is different at different times of the year.
In January, the sun is moving more rapidly eastward as seen from earth. The rotation of the earth still moves it westward across the sky, but a little more slowly, making the apparent days slightly longer. The time of the sun being highest in the sky goes from 12:03 at the start of the month to 12:13 at the end. The times of sunrise and sunset change in the same way.
If we still kept sundial time, instead of mean time, the sunrise and sunset times would change symmetrically. Advanced countries made the change around 1800, as people’s clocks became accurate enough for days of variable length to become annoying.
(Edit: times of noon corrected)
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