The shortest day of the year, the longest night occurs today, Sunday, December 21st. The so-called Winter solstice is an astronomical phenomenon that occurs in the North Hemisphere when the Earth North axis is at the longest distance to the sun. The phenomenon has to do with the elliptical orbit of the Earth and the sun’s elevation in the sky is the lowest.
Did you know that meaning of “solstice is that “the sun stands still”?
The phenomenon of Winter Solstice lasts only a moment. The moment the the North Pole is tilted furthest from the sun as the Earth continues on its orbit. The phenomenon will occur at 22:03 GMT, says the BBC, adding that
“The solstice doesn’t always occur on 21 December. Sometimes it nudges into the early hours of 22 December, which will happen again next year. The hour of day also varies. Last year’s arrived at 17:11. Next year’s will at 04:38.”
An interesting note, is that while days get longer, the mornings get darker!
“It would seem logical that after the shortest day has elapsed the mornings would start getting lighter earlier, but this isn’t what happens – the mornings continue darkening until early in the new year.”
Primary reason for this “dark mornings” is that the solar days do not last exactly 24 hours as our clocks “claim”.
“In fact, it is 24 hours only four times a year, and never in December,” explains astronomer Stephen Hurley, who runs a popular science blog called The Science Geek. “It is at its shortest around 23 hours 59 minutes and 30 seconds, in early September, and at its longest around 24 hours 30 seconds in December.”
The sun therefore in effect lags behind the clock for part of the year, then speeds ahead of it for another.
“As you can imagine, it would be complete chaos if our clocks and watches had to cope with days of different lengths,” continues Hurley. “So we use 24 hours, the average over the whole year, for all timekeeping purposes.
“So, as the solar days in December are on average 24 hours and 30 seconds, while our clocks and watches are still assuming that each day is exactly 24 hours, this causes the day to shift about 30 seconds later each day.” (full article here)
Independently of whether our clocks are correct or not, fact is that from now on, and until June 21st, night will get shorter and days will turn longer. One minute per day.
Therefore, from now on, things can only get better 🙂
more information in December Solstice
