Winter Begins
"Winter Begins" marks the astronomical transition into winter in the Northern Hemisphere, occurring around December 21 or 22 each year with the winter solstice. This event is characterized by the Sun reaching its southernmost point in the sky, resulting in the shortest day and longest night of the year. The concept of winter as a season is defined by the Earth's tilt and elliptical orbit, leading to colder temperatures and less solar radiation. In historical contexts, winter has been perceived as a time of dormancy and struggle, often associated with various cultural and religious traditions that celebrate the return of light and warmth. Many ancient civilizations held ceremonies and rituals during this period, with the winter solstice being significant in mythological narratives. In addition, the solstice has influenced art and literature, symbolizing a time of contrast between hardship and celebration. While the Northern Hemisphere experiences winter starting in December, the Southern Hemisphere sees the opposite seasonal change beginning in June. Overall, "Winter Begins" encapsulates both the scientific and cultural dimensions of this pivotal time of year.
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Winter Begins
Winter Begins
In the United States and the north temperate zones generally, winter begins December 21 or 22. The precise moment at which the Sun reaches the winter solstice, formally signaling the change of seasons, varies slightly every year as a result of the many oscillations that the Earth undergoes during its annual elliptical journey around the Sun and its daily rotation on its axis.
Like the other three seasons, winter has an exact astronomical beginning. The ecliptic, namely the plane on which Earth revolves around the Sun, is divided into four equal 90 degree sections. Each has a specific starting point. While spring and autumn commence at the vernal and autumnal equinoxes respectively, winter and summer begin at their respective solstices. The winter solstice (Latin solstitium meaning "solstice," from sol meaning "Sun" and sistere meaning "to stand still") is situated midway between the autumnal equinox and the vernal equinox. The amount of time the Sun requires to traverse the 90 degree section from the winter solstice to the vernal equinox is known as the season of winter.
Winter is also said to begin when the Sun enters the tenth sign of the zodiac, namely Capricorn or "the Goat." This assertion is actually anachronistic. At the time of Hipparchus, the second-century BCE Greek astronomer who laid the basis of the zodiacal system, the winter solstice began at Capricorn. However, precession, as the retrograde motion of the equinoctial points on the ecliptic is called, has caused each of the twelve constellations of the zodiac to move 30 degrees backwards during the course of the past 2,000 years. The winter solstice is now located in the constellation Sagittarius or "the Archer." Only at the completion of a 25,800-year cycle will it once again be situated in Capricorn.
In the Northern Hemisphere, the Sun shines at its weakest during the time of the winter solstice because it then attains its southernmost position in the skies. At its maximum southern declination (a term used by astronomers to correspond with terrestrial latitude), the Sun extends its rays across and beyond the Earth's South Pole as far as minus 23 degrees 27 minutes. Similarly, its rays fall 23 degrees 27 minutes short of the North Pole, striking only the near side of the Arctic Circle. At the same time, the Sun has a longitude of 270 degrees. Thereafter for a few days the Sun seemingly "stands still," so much so that the times of sunrise and sunset differ imperceptibly, and the days appear to be of equal length. During the rest of winter, the Sun's southern declination continuously diminishes until the vernal equinox, at which time the Sun reaches both a longitude of 0 degrees and a declination of 0 degrees, thereby completing the yearly cycle of the seasons.
The difference in the seasons, especially the variation in weather, is due to the 23-and-a-half-degree tilt of the Earth's axis and to its elliptical revolution around the Sun. Around December 21 and 22, the North Pole is inclined directly away from the Sun. Since the Sun's rays are slanted, the Earth's atmosphere and surface are exposed to a low amount of daily solar radiation. Consequently, temperatures are cold, even freezing. The most extreme cold wave generally occurs around the beginning of February. In the Southern Hemisphere, as the result of the reverse movement of the South Pole, the seasons are also reversed. Astronomical winter begins around June 21 and ends around September 21.
Winter has a distinct character in the Northern Hemisphere above the Tropic of Cancer. As the season of dormancy, darkness, and cold, it greatly impressed the ancients. They regarded this period of the year as a time of crisis during which the deities of the upper world struggled against the spirits of chaos and evil to assure the return of light, warmth, and fertility. In the Western world, many pre-Christian seasonal traditions marked the winter solstice, as people of various cultures observed what they deemed to be a significant religious occasion. Huge bonfires were an integral part of elaborate solar rites. As the days slowly lengthened and gave promise of eventual spring, a less solemn and more festive mood ensued. Roman worshipers of the Persian sun god Mithras celebrated December 25 as the dies solis invicti nati, the "birthday of the invincible Sun." The date of Christmas was probably fixed for this same day because it coincided with and offered competition to these alternative festivities.
The winter solstice played an important role not only in mythology and religion, but also in art and literature. For example, early basilicas and medieval cathedrals were frequently adorned with symbolic representations of the seasons and of the individual months. Some of the carved stone scenes depicting the calendar year show winter as a season of contrasts between the laborious preparations for the rough wintry days ahead and the Christmas revelries.
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