An extra second will be added to 2005 to make up for the slowing down of the Earth's rotation, officials said this week.

　　The once-common "leap second" is the first in seven years and reflects the unpredictable nature of the planet's behavior.

　　The International Earth Rotation and Reference Systems Service in Paris keeps track of time by measuring the Earth's rotation, which varies, and by an atomic clock, which is unwavering. When a difference in the two clocks shows up, the IERS adds or subtracts a second to the year.

　　For the first time since 1998, the IERS will sneak in an extra second this year to get time back in synch, officials said in a statement Monday.

　　On Dec. 31, the clock will read like this as it leads into Jan. 1, 2006: 23h 59m 59s ... 23h 59m 60s ... 00h 00m 00s. Normally, the seconds would roll from 59 directly to 00.