Tuesday 30 November 2021
Dr. Gad El-Qadi, head of the National Institute for Astronomical and Geophysical Research, said that winter will begin in the northern hemisphere on Tuesday, December 21, at about six oclock in the evening local time in Cairo, and will last for about 88 days, 23 hours and 35 minutes.
Al-Qadi added that the day of that day will be the shortest day in 2021, and its night is the longest night, and the shadow of man on earth will be the longest possible.
He explained that on this day, the Earth’s south pole will be tilted towards the sun, which is at this time directly above the Tropic of Capricorn at 23.44 degrees south latitude, and the sun reaches its lowest height in the sky at noon when it crosses the meridian.
The winter solstice occurs in the northern hemisphere around December 21 or 22 of each year, when the sun reaches its lowest height during noon above the horizon, and the sun’s rays are very inclined on the northern hemisphere and almost perpendicular to the southern hemisphere, except for the Tropic of Capricorn. It is an annual astronomical event characterized by the verticality of the sun over the course of Capricorn, and the conditions of the globe during the winter solstice in the northern hemisphere and summer in the southern hemisphere are reversed at the same time, while in the northern hemisphere it is winter and it is summer in the southern hemisphere.