Today is the day that the dark, or night time, lasts the longest it will the entire year ... at least for those of us in the Northern Hemisphere. Going forward, until Summer Solstice, the nights will get shorter and shorter for us. Interestingly, as Santa prepares at the North Pole, the sun will not shine at all today for him. Hopefully he has lots of Christmas lights on. :)
Night time helps us appreciate day time, and day time helps us appreciate night time. It is the severe contrast that brings us the beauty of the other. Living in total dark, or living in total light, would mean never being able to appreciate the other.
On this day, we celebrate the beauty of contrasts and ensure we are enjoying all that contrasts have to offer us in life.