In one hemisphere, the winter solstice is the shortest day of the year, while the summer solstice is the longest. The onset of winter is marked by the December solstice, when the South Pole is tilted closest to the Sun and the Sun's rays are directly above in the Tropic of Capricorn. At this time, the axis of Earth's rotation is also at its most northward inclination, causing the Northern Hemisphere to experience winter and the Southern Hemisphere to experience summer.
The astronomical cause of this effect is that the axial tilt of Earth's orbit around the Sun causes each hemisphere to experience a period of seasons consisting of warm days and cold nights. The amount of landmass covered by ice and snow increases during this time, since more of the planet is exposed to the sun. As the years progress, the amount of land covered by ice and snow decreases again because more and more of it is lost through evaporation.
On the summer solstice, the South Pole is tilted away from the Sun, so the Southern Hemisphere experiences spring and the Northern Hemisphere experiences autumn. But the axis of Earth's rotation is still in its lowest position relative to the sky, so both hemispheres experience seasons with long nights and short days.
The astronomical reason for this effect is that at the beginning of the year, the vernal equinox occurs when the North Pole is tilted toward the Sun and the south pole is tilted away from it.
The Northern Hemisphere's winter solstice happens on December 21 or 22, when the sun appears in its most southerly position, straight overhead at the Tropic of Capricorn (23 degrees, 27 minutes south latitude). The winter solstice is the shortest day of the year, signaling the start of winter. During this time, the days are getting longer, but not by much; it will still be dark outside for several more hours.
The end of winter solstice marks the beginning of spring and the return of daylight saving time. Until the advent of electricity, the lighting of candles was essential for night time work or entertainment. They were used during Roman times and later as well.
During the Victorian era, people would wear clothes that exposed as little skin as possible. Clothing was made from cotton, which grows in bolls within the plant. When harvested, the cotton goes into a gin to remove the seeds and fibers from the inside of the pod. This leaves behind a long strand of cellulose, which is ready to be spun into yarn. Yarn is then woven into fabrics. In order to keep animals from eating the crops, they were planted with flax, hemp, or linen. These materials were also used for clothing.
People throughout history have tried different methods for keeping warm. Fire has always been important for warmth, but it can be dangerous as well. Incendiary weapons such as guns and torches allow humans to use fire for protection instead of destruction.
The Northern Hemisphere is leaning the most away from the sun for the year at the December solstice. The solstice marks the shortest day of the year for those of us in the northern hemisphere. The days become longer and the nights become shorter after the winter solstice. This is because we are entering a period where the axis of the earth is tilted with respect to the orbit of the sun.
At the time of the winter solstice, the North Pole is closest to the sun while at the summer solstice, it is farthest away. During a total solar eclipse, the Earth's atmosphere refracts light from the Sun that reaches its surface. The part of the atmosphere that causes this effect (known as the "eclipse path") bends around areas where there are large amounts of water or ice. Because the distance between the Earth and the Sun is greatest at the winter solstice, more of the Sun's rays are blocked by the atmosphere during a total solar eclipse at this time than at another season of the year.
Total solar eclipses are visible on all but the far north and south poles. If you're looking directly at the center of the eclipse, only the outer ring of the moon is illuminated; if you look to the left or right of center, you will see both the inner and outer rings of the moon illuminated.
People have been recording solar eclipses for thousands of years.
The winter solstice happens annually on December 21 or 22 in the northern half of the Earth (the Northern Hemisphere). (The winter solstice occurs on June 20 or 21 in the Southern Hemisphere.) The winter solstice is the day with the fewest hours of sunshine in the whole year, making it the year's "shortest day."
People have been observing the winter solstice for many centuries because they needed to know when to plant crops and when to expect a return of fertile soil. Scientists have also studied the winter solstice because of its importance in predicting solar activity and the behavior of ice ages.
The ancients celebrated the winter solstice with rituals that included dancing, music, feasting, and gift giving. Modern-day Christmas celebrations include some of these elements along with more: candlelit nativity scenes, decorating trees, singing carols, giving gifts, and so on.
The winter solstice was once known as Yule or Joule. It comes at the end of the old year and the beginning of the new year by ancient European tradition. Today, it is called Santa Claus Day or Christmastide and begins on December 25. It is followed by the first day of spring, which in most parts of the world is March 20. However, in the Southern United States, April 19 is considered the first day of spring.