This has been a vey long year, besides being a leap year with February 29th being on the 2008 calendar, an international consortium of timekeepers have decided to add an extra second to 2008. The Earth's rotation has been slowing down and to keep our clocks accurate an extra second had to be added to 2008.
The Leap Second
According to the National Institute of Standards and Technology (NIST), the spin of the Earth is slowing down, about 0.002 seconds. The varying rotation of the Earth is due to the cumulative effect of friction from the ocean's tides, the Moon’s orbital momentum, snow (and the lack thereof) at the polar ice caps, the 23-degree tilt of the Earth, the atmosphere, solar wind, space dust and magnetic storms. In any case, the Earth does not rotate exactly once every 24 hours (or 86,400 seconds). Thanks to precise measurements of the position of the Earth relative to the stars made possible by the atomic clock, the Earth’s rotation was found to be gradually slowing down. It was decided by international agreement in 1972 that operators of atomic clocks around the world adjust the time of day by adding one second to the world’s official time when needed. This keeps Coordinated Universal Time (UTC) in sync with astronomical time—that being the position of the sun above the Earth—and the leap second was born Photo of Atomic Clock: Michael Smith/Getty Images