The winter solstice - the shortest day of the year

On Friday, 22/12/23 at 05:26 viewers from Jerusalem will have the point in time where the length of the day reverses, autumn ends and winter begins in the Northern Hemisphere. The length of the day is ten hours and four minutes

Winter solstice versus summer solstice. Illustration: depositphotos.com
Winter solstice versus summer solstice. Illustration: depositphotos.com

Winter begins on the day of the winter solstice, which fell this year on December 22 at 05:26 am for observers from Jerusalem. This is the day of the year when the sun's path in the sky is at its southernmost point relative to the equator. On this day the sun's path is the shortest, resulting in the shortest day and longest night of the year.

The sun will rise on 22/12/2023 at 06:35 and set at 16:39, which means the length of the day is ten hours and four minutes and a half 10:04:29).

In the days before the winter solstice the days get shorter, then on the evening of the solstice the astronomical winter begins. From this point the days lengthen until we reach the summer solstice and the longest day of the year.

The reason for the seasonal changes is the tilt of the earth's axis, which is about 23 degrees. Thanks to this tendency, different regions of the Earth receive different amounts of sunlight throughout the year. Without this tendency, we would have no seasons at all.

At the time of the winter solstice, the North Pole is tilted about 23.4 degrees away from the sun, so the sun's rays move south from the equator. This results in the shortest day and longest night in the Northern Hemisphere.

As we know, there are two winter solstice days each year - one in the northern hemisphere and one in the southern hemisphere. While we experience the winter solstice, on December 21/22, those living in the southern hemisphere are on their summer solstice.

The winter solstice and the summer solstice are completely opposite to each other. If one of the days symbolizes the shortening of the day, the other symbolizes its lengthening. If one of the days marks the point where the Earth's axis is tilted the farthest from the sun, the other marks the point where the axis is tilted as close as possible to the sun.

The winter solstice has a deep meaning in the mythology and folklore of many cultures throughout history. It symbolized a time of rebirth, as it symbolized the lengthening of the days after the darkness of winter. There are many celebrations and festivals associated with this day. We are of course familiar with Hanukkah - the festival of lights that takes place more or less around the winter solstice.

Early Christianity adopted the date of December 25 as the day of Christ's birth, to weaken pagan celebrations that took place around the winter solstice. Remnants of these pagan traditions remain in the modern celebrations of Christmas. 

Many fairy tales deal with the theft of the sun or its death and rebirth around the winter solstice. But as our understanding of the solar system developed, the superstitions surrounding this day faded. Still the tradition of family and community celebration on this day was preserved.

In order to understand the winter and summer solstices, we need to understand a basic fact - the earth's axis of rotation is tilted approximately 23.5 degrees compared to the plane of its orbit around the sun. This means that the Earth's orbit oscillates as it orbits the Sun throughout the year. In this situation, the different hemispheres are exposed to a varying amount of sunlight, when this tendency causes the sunlight to hit the surface of the earth at different angles at different times of the year.

In summer we see the sun for longer periods and it appears high in the sky. The sun's rays are more direct and the heat energy is more widespread. In winter, when the sun is low in the sky and visible for a smaller number of hours, less energy reaches the ground and therefore the sun heats less efficiently.

Those who live near the equator will notice almost no difference in the amount of sunlight they receive throughout the year. The biggest difference is at the poles, where each reversal brings the number of daylight hours to extremes. In the summer the sun never sets for weeks, and in the winter it never rises creating some of the most uncomfortable environments on Earth.

More of the topic in Hayadan:

Comments

  1. I am intrigued to know how the climate zones in the world (and in Israel in particular) would look like if the earth was not tilted on its axis.

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