Why does the earliest sunset fall on a day weeks before the winter solstice?

Question

Or the latest sunrise fall on a day weeks after the winter solstice? The winter solstice may be the shortest day of the year, but it's not the day of either earliest sunset nor latest sunrise. For the southern hemisphere, the situation is shifted to the summer solstice.

For help in finding sunset and sunrise times around the around for different times of the year, here's a link you can use. http://www.sunrisesunset.com/custom_srss_calendar.asp

Answer 1

The simplest way to explain is to say we base our clocks clocks/calendars based on approximations of the earth's rotation and earth's path around the sun.

The actual length of a solar day (the time it takes the earth to spin around on it's axis once) changes from month to month. Near the winter and summer solstices it's actually more than 24 hours, and in the vernal (spring) and autumnal (fall) exquinox it's less than 24 hours.

The reason for the variation actually has to do with the obliquity (oval instad of exactly circular ) of the earth's path around the sun.

Those two things combined with the tilt of the earth's axis makes for the variation in length of days, and thus the slight difference between the equinox and the 'earliest sunset'.

For more explicit details see the links below.

Answer 2

There really is no easy way to explain why this happens. It is easier to understand with a picture. Some may say it is due to the Earth's slightly elliptical orbit of the sun, but this isn't true. The elliptical orbit affects it but even if Earth's orbit was perfectly circular, this effect would still occur. You might find the answers you seek at http://www.analemma.com

Update: I'll try to explain it as best I can. The length of the solar day (the time between lower culminations of the sun, ie midnight to midnight) is not constant. Some days it is shorter than others slightly. This is due both to Earth's axial tilt and it's slightly elliptical orbit of the sun. The average solar day is exactly 24 hours (and 2 milliseconds technically). From day to day though, the length varies. Because of this variation, your true local time will begin to deviate from your local solar time (time measured by the position of the sun). This variation is cyclical, and it is called the equation of time. This equation tells you how far off true local time is from local solar time. It moves between around -16 to +15 minutes over the course of the year. It is this slight variation that causes the earliest and latest sunsets and sunrises to be at different dates than the solstices. The closer you are to the equator, the further these earliest and latest events will be from the solstices.

If the solar day were always exactly 24 hours then this phenomenon would not occur.

Answer 3

The time by potential of the solar varies by potential of plus and minus 12 minutes in the time of the 300 and sixty 5 days by using fact our orbit is an Ellipse. this version occurs quicker than the fee of substitute of inclination of the Earths axis on the Solstices. observe the commonplace of your 2 days is somewhat on the brink of the solstice date.