The solstice of winter in the southern hemisphere happens in this Thursday (20) at 5:50 pm (Brasília time), according to the National Observatory. Marking the beginning of a new seasonthe event symbolizes changes in the length of days and nights.
The reason for this is that as the Earth orbits the Sun, the 23.5° tilt causes one hemisphere to be tilted toward the Sun for half of the year and the other for the second half. On this date, there is the shortest period of light and the longest night of the year.
Astronomers of ancient civilizations defined solstices by observing the movement of the Sun across the sky throughout the year. After studying where the star was every noon, they noticed that it reached a maximum point and seemed to “stop”.
This “stop” occurs twice a year and corresponds to the summer and winter solstices. During the June event, the Southern Hemisphere is tilted away, while the Northern Hemisphere is tilted toward the Sun.
Cultures around the world have built monuments to observe the Sun, such as Stonehenge in England, and have defined celebrations to mark the transitions between the seasons.
Yule, the festival of the ancient Norse and Germans, lasted several weeks in which they decorated trees and performed rituals to honor the return of light. In ancient Rome, Saturnalia honored the god Saturn a few days before the winter solstice. The celebration included banquets and the exchange of gifts.
Winter Solstice
In the southern hemisphere, this event takes place between the 20th and 21st of June, as there is a difference between the calendar year (which has 365 days) and the tropic year (which has approximately 365 days and 6 hours).
On this date, the southern part of the Earth receives less solar radiation than the northern hemisphere, with the day lasting less than the night.
The winter solstice marks the point of inclination of our planet’s axis, which points further from the Sun and, from there, the periods with sunlight become increasingly longer, until summer arrives and reverses this dynamic.
Summer Solstice
Due to the Earth’s tilt, from this point onwards, the sun’s rays reach one hemisphere more directly. Therefore, the days are warmer and there are more hours of light, making them longer than the nights.
On the day of the solstice — between the 21st and 22nd of December in the southern part of the globe — the longest day of the year takes place, which gets shorter until the next event, winter.
At the beginning of the other seasons — spring and autumn — the equinoxes occur, when the length of day and night is almost the same in all parts of the world.
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