Today, December 21, 2013, marks the winter solstice in the northern hemisphere.
According to our friends at Wikipedia, “The axial tilt of Earth and gyroscopic effects of the planet’s daily rotation keep the axis of rotation pointed at the same point in the sky. As the Earth follows its orbit around the Sun, the same hemisphere that faced away from the Sun, experiencing winter, will, in half a year, face towards the Sun and experience summer. Since the two hemispheres face opposite directions along the planetary pole, as one polar hemisphere experiences winter, the other experiences summer.
More evident from high latitudes, a hemisphere’s winter solstice occurs on the shortest day and longest night of the year, when the sun’s daily maximum elevation in the sky is the lowest….The seasonal significance of the winter solstice is in the reversal of the gradual lengthening of nights and shortening of days.” (source)
Our science kitteh has kindly agreed to cut back his daily napping from twelve hours to ten for the occasion, with the proviso that he can attack the Christmas tree with impunity during the year’s longest night.