6 facts about the winter solstice
Throughout human civilisation, the winter solstice has been an important milestone in the calendar. Marking the shortest day and the longest night, across the globe many cultures have celebrated it with holidays and festivals. Find out more with these 6 facts:
1. The magic moment
While many focus on the winter solstice as a day in the calendar, what we are actually talking about is a very specific moment which is over almost as soon as it has begun.
The solstice marks the point at which the Sun is exactly overhead the Tropic of Capricorn which this year will happen on Wednesday 21 December at 16:28 GMT.
2. The sun stands still
Like many other astronomical terms, the word solstice comes from Latin. Owing to the sun appearing to 'stand still' in the sky when it reaches the Tropic of Capricorn, the word solstitium was used which in turn is composed from the words sol (meaning 'sun') and sistere (meaning to 'stand still').
3. Winter begins
As well as marking the shortest day of the year, the winter solstice marks the first day of the season of winter in the astronomical calendar, whilst in the meteorological calendar, we are already three weeks into winter.
4. Nine hours darker
You're probably aware that the day of the winter solstice marks the shortest day of the year, but did you know that its almost nine hours shorter than the longest day of the year?
The summer solstice in June is just short of 16 hours and 38 minutes long, while on the day of the winter solstice the length of the day is a mere 7 hours and 50 minutes.
5. The earliest sunset
Logically you'd expect the earliest sunset to fall on the shortest day, but the earliest sunset actually occurs a few days earlier in the calendar and it's all to do with our clocks not quite mirroring the earth's orbit.
True solar noon - the point at which the sun reaches its highest point in the sky - occurs around 10 minutes earlier than when our clocks strike 1200, and it is this discrepancy that means the sunset also arrives a little later on the solstice.
6. Solstice and Christmas
Amongst the many festivals that centre around the solstices and equinoxes, the Scandinavian festival of Jul has some rituals that are probably more familiar than you think.
Perhaps more familiar to us as Yule, the 12-day festival centred around the solstice has given birth to many of our most familiar Christmas traditions including the Christmas tree, the Yule log and the Christmas wreath.