Today, the 12th of December 2008, we have the earliest sunset of the year in the Northern hemisphere. In Greenwich, the Sun sets at 15:50GMT.

The earliest sunset occurs on a different day to the solstice due to a combination of the Earth's elliptical (oval-shaped) orbit and it's tilt. Put together, these two effects are known as the Equation of Time, the difference between what an averaged mechanical clock will say and what a Sun dial will say.