The Longest Night

As many of you may know, today is the Winter Solstice - the official start of winter and the date on which there is the shortest day and longest night. So for those of you with S.A.D. (that's season affective disorder), today is when those nights will slowly start to get shorter. This also means no more walking home in the dark at 5 pm. What some of you may not know (although i'd be surprised) is that the day over in the UK will actually be shorter than the day here (likewise the UK will have a longer night). And this is in large part to what's happening with the Earth itself.

Y'see the seasons are caused by the fact that the Earth is not completely vertical on its axis, leaning instead 23 degrees and 27 minutes off it. This planetary pose is what causes all the variety of our climate as it is a major factor in determining how many hours and minutes each hemisphere receives precious sunlight. Thus, the winter solstice is when, because of the earth's tilt, your hemisphere is leaning farthest away from the sun. This is also why there are the Tropic of Cancer and Tropic of Capricorn latitude lines - on thhe winter solstice, the sun is only directly overhead at noon on the Tropic of Capricorn - likewise, on the Tropic of Cancer at Summer Solstice. Thus, the distance you are from these lines will dictate how many hours of daylight and night you will get. This is also why places in the far North have six month long nights - cause the sun is so low in the sky as to be over the horizon. Happy Solstice to all!