Don’t forget to change your clocks on New Years Day! The International Earth Rotation and Reference Systems Service has announced that December 31, 2005, will include a “leap second.” That is, there will be 86,401 seconds on the last day of the year instead of the usual 86,400. This leap second will keep our clocks more or less synchronized to the rotation of the earth, which fluctuates slightly due to the winds and ocean currents, motion of the fluid core and tidal and current friction at the ocean floor. The last leap second occurred on December 31, 1998 and this upcoming leap second might be the last one! The U.S. has proposed abolishing future leap seconds as the adjustment is primarily made for the sake of navigators making traditional astronomical observations with sextants. Global Positioning System (GPS) operations are unaffected by the introduction of a leap second, because its time, GPS Time is not adjusted. Just thought you should know!