Earth's rotation has slowed again
For the first time in seven years we will have to add a second to the Atomic Clock for the year 2005 to allow for the rotation of Earth slowing down.
The current standard is a cesium atom, which vibrates 9,192,631,770 times per second. As far as scientists know, this doesn't change over time and is the same everywhere on Earth and in space.
Livescience.com