The celestial phenomenon marking the shift in weather and daylight patterns, colloquially referred to as the Winter Solstice, takes place annually on the 21st of December. This day signifies the shortest day of the year in the Northern Hemisphere, while the Southern Hemisphere concurrently experiences its longest day, known as the Summer Solstice.
Understanding the Solstice
Originating from Latin, the term ‘solstice’ translates to ‘stalled sun’. This natural event occurs biannually, surfacing once each during the summer and winter seasons in both hemispheres. The solstice represents a significant marker in Earth’s journey around the Sun.
The Winter Solstice: A Closer Look
The Winter Solstice signals the first day of winter or the ‘Hiemal’ or ‘Hibernal’ solstice within the Northern Hemisphere. Characterized by the shortest day accompanied by the longest night of the year, the Winter Solstice occurs primarily because countries in this hemisphere are at their greatest distance from the Sun.
During this time, the Sun shines directly overhead on the Tropic of Capricorn, located at 23.5 degrees south. Similarly, the Tropics of Cancer and Capricorn are situated 23.5 degrees north and south of the Equator, respectively. The Arctic and Antarctic Circles lie farther out at 66.5 degrees north and south, forming crucial components of geographic latitudes – which measure a location’s distance from the Equator.
Come June 21st, the Northern Hemisphere will experience its Summer Solstice or the year’s longest day, as the Southern Hemisphere gears up for its shortest day.
Cultural Significance of the Winter Solstice
This astronomical event holds deep-rooted cultural and traditional importance. The Surya Siddhanta, an essential component of Vedic tradition, implicitly recognizes the northward motion of Earth on the celestial sphere. Therefore, the Winter Solstice is commemorated as the first day of Uttarayana – a period stretching between the Makar Sankranti and Karka Sankranti festivals.
A Special Winter Solstice in 2020
The Winter Solstice of 2020 held an additional layer of significance due to its coincidence with a rare celestial event commonly known as the ‘Great Conjunction’ of Jupiter and Saturn. This conjunction, which refers to the two planets sharing the same right ascension or celestial longitude, visibly came into action after almost 400 years.
The Geography Behind Changing Day Lengths
The Earth’s tilt plays a critical role in determining variations in day lengths. Tilted at an angle of 23.5 degrees to its orbital plane, Earth’s axis of rotation, coupled with factors such as Earth’s spin and orbit, cause significant fluctuations in the durations of sunlight.
Consequently, any location on our planet experiences varied day lengths throughout the year. For half the year, the Northern Hemisphere tilts towards the Sun, resulting in longer days with direct sunlight – characteristic of the summer season. For the remaining half, the hemisphere tilts away from the Sun, marking shorter days and the onset of winter.
This tilt has a profound effect on Earth’s seasons, orchestrating the Sun’s movement from the northern hemisphere to the southern and back, thereby dictating seasonal changes throughout the year.