Saturday, 30 June 2012

How shall I spend the time?

From: The Connexion - France's English language newspaper:

GET A long lie on Sunday morning as scientists add an extra second to atomic clocks to keep them in time with the rotation of the Earth.

The "leap second" will be added just before midnight Coordinated Universal Time on Saturday - at 2.00 in France. For a brief moment the time will be 01:59:60 before flipping to 02.00.

This is the 34th time that the leap second has had to be added to cater for the change in the way the Earth wobbles on its axis as it rotates round the Sun. The last one was in 2008.

Daniel Gamis, director of the International Earth Rotation and Reference Systems Service which monitors timing systems at the Observatoire de Paris, said that the length of the day on Earth was slowing down.

This is because of the actions of tides and the reactions of the Earth's core, while violent earthquakes such as Fukushima can also upset the planet's rotation.

The Earth takes 86,400 seconds for a full 360-degree rotation but tides slow it down by 1.4 milli-seconds a day - meaning that in around 300 to 400million years the day will be just 22 hours long.

Since 1967 governments had agreed to move away from solar time and towards the precise measurements from atomic clocks but also agreed to adjust International Atomic Time to get rid of the discrepancy between the two.

The adjustment is generally every two years or so, but an unusual speeding up of the Earth meant it has not been needed since 2008.

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