Astronomical Winter Begins, Marking Year’s Shortest Day
Astronomical winter begins in the northern hemisphere with the winter solstice on December 21. This event marks the shortest day of the year and consequently the longest night. Diverse cultures have celebrated this phenomenon throughout history.
Historical Celebrations of the Winter Solstice
One notable celebration is Saturnalia from Ancient Rome. This festival lasted for a week and included feasting, gift-giving, and a unique social dynamic where masters served their slaves.
Scientific Significance of the Winter Solstice
The winter solstice occurs when the Earth’s north pole is tilted furthest away from the sun. This positioning results in the sun appearing at its southernmost point in the sky. Consequently, it rises only to its lowest noon altitude from the northern hemisphere.
Contrasting Seasons in Hemispheres
- In the northern hemisphere: winter solstice marks the shortest day.
- In the southern hemisphere: the situation is inverted, leading to the summer solstice, which has the longest day.
Although the astronomical definition sets the start of winter at the solstice, meteorological winter begins earlier on December 1. This differentiation is important for various climatic and cultural reasons.
Daylight Increases after the Solstice
As winter progresses, residents in the northern hemisphere will notice increased daylight. Following the winter solstice, the sun will gradually rise higher at noon, extending the length of each day.
