Talvipäivänseisaus

Talvipäivänseisaus, also known as the winter solstice, is an astronomical event that occurs twice each year. In the Northern Hemisphere, it typically falls around December 21st or 22nd, marking the shortest day and longest night of the year. Conversely, in the Southern Hemisphere, the winter solstice occurs around June 20th or 21st, also signifying the shortest day and longest night in that hemisphere.

The phenomenon is caused by the Earth's axial tilt. As the Earth orbits the Sun, its axis is tilted at approximately 23.5 degrees relative to its orbital plane. During the winter solstice, one of the Earth's hemispheres is tilted furthest away from the Sun. This results in the Sun appearing at its lowest point in the sky at noon, and consequently, the least amount of daylight.

Throughout history and across various cultures, the winter solstice has held significant cultural and symbolic meaning. It has often been associated with themes of darkness yielding to light, the rebirth of the Sun, and the turning point of the year. Many ancient festivals and celebrations, such as Yule, were held around this time to mark the end of the darkest period and the anticipation of returning daylight and warmer seasons. Astronomical observations and accurate prediction of the solstice have been a testament to early understanding of celestial mechanics.