[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
I guess the fundamental reason is that the axis of rotation of the earth is slanted with respect to the plane it revolves around the sun and that the path around the sun is an ellipse.
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)
An average solar day is 24 hours. Any specific day can be a bit less than 30 seconds longer or shorter. That means the middle of a solar day, solar noon, changes and is not always at the same time. This is in large part because Earth orbit around the sun is elliptical, not circular.
Sunset and sunrises are symmetrical around solar noon, not the close we used that is based on average solar noon
On 1/1/24 solar noon is at 12:40 sunrise is at 7:42 and sunset is at 17:39. That is a sunrise 4:58 before solar noon and a sunset at 4:59 after solar noon. The difference is because the times do not include second and that the length of days increases a bit during that period
On 31/1/24 solar noon is at 12:50 sunrise is at 7:35 and sunset is at 18:07. That is a sunrise at 5:15 before solar noon and sunset at 5:17. That is within the margin of error of the numbers.
So both sunrise and sunset change the same around solar noon, solar noon change 10 minutes too.
This shows how solar noon changes relative to average solar noon https://en.wikipedia.org/wiki/Analemma#/media/File:Analemma_Earth.png A 4 degrees diffrence is close to 16 minutes.
If you look at February you will notice it starts and ends with close to the same offer. Solar noon in the linked location is at 12:51 and Feb 1 and at 12:49 on Feb 29
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