By: Joe Rao
Winter in the Northern Hemisphere will officially arrive tonight with the rays of the sun shining directly down on the Tropic of Capricorn — latitude 23.43-degrees south — at 10:27 p.m. Eastern Time. At that moment, if you were located in Western Australia at a point near Lake MacKay, the sun will be shining directly overhead and its six-month southward migration will come to an end, marking the beginning of summer for the Southern Hemisphere.
Indeed, the word “solstice” is derived from sol, the Latin word for “sun.” The ancients added sol to sistere, which means “to stand still” and came up with solstitium. Middle English speakers shortened solstitium to solstice in the 14th century. The effect is an artifact brought about by the change of the seasons, which can be readily explained today by astronomers.
Our planet is tilted on axis by 23.4-degrees. So, as Earth moves around the sun once each year, there comes a time when the sun shines more on the Northern Hemisphere — summer for us; sometimes more on the Southern Hemisphere — that’s winter for us. And between each of these two extremes, there comes a time when the sun shines in equal amounts for a whole day on all parts of the planet — the equinoxes.
Sun rides high … and low
From the Earth, it seems to us just as it seemed to people even before the dawn of history, that the sun moves in the sky. On the first day of summer, we see the sun high in the sky at noon. It rises about 8 hours before noon and sets about 8 hours after noon and correspondingly the weather gets warm. At the fall and spring equinoxes, the sun is in the sky for just about 12 hours. But on the first day of winter, the sun is the sky a total of only about 8 hours and it appears very low in the sky at noon. As a result, we get cold from so little exposure to the sun.
Now in ancient days, people had no understanding of the mechanics of the universe. They thought that something might break down some day and the sun would continue its southward journey never to return. The lowering of the sun was cause for fear and wonder. When they saw the sun stop and slowly began its climb to a higher location, people rejoiced: They felt a promise that spring would return.
Read more at: https://www.space.com/winter-solstice-2023-longest-night-northern-hemisphere