Today is the winter solstice, the shortest day.
Planet Earth is tilted on its axis. During the northern hemisphere’s winter, the axis is tilted away from the sun and the nights are longer than the days; in the southern hemisphere it is summer and the earth’s axis is tilted towards the sun.
This diagram was published by NASA, who know what they are talking about when it comes to the solar system.
At the arctic circle, at latitude 66.5°N, the sun won’t rise above the horizon at all today; at the North Pole the sun hasn’t risen since the autumnal equinox on September 23rd.
Today, in the UK, the sun rose at 08.12am and will set at 04.03pm: just seven hours, 49 minutes and 43 seconds of full daylight. Tomorrow the day will be longer and by March 20th, the vernal equinox, it will be the same length as the night.
As far as we can tell, people have always celebrated this turning of the year. All our winter festivals, no matter what religion we dressed them in, are adaptations of solstice celebrations that go right back into prehistory.
In the park, day length is an important trigger for so many of our species. The solstice is a signal that turns on the processes of growth and regeneration.