The Big Ben |
If you are one of those people who can’t wait for 2016 to be over, then bad news – you’ll have to wait a second longer.
Yes, a whole extra second.
Counting down to 2017 will take longer than usual this New Year’s Eve to compensate for a slowdown in the Earth’s rotation.
Timekeepers
at the National Physical Laboratory (NPL) are introducing a “leap
second” after 23:59:59 on December 31 – delaying midnight by a second.
We have to add, though, this isn’t the first time NPL has added a leap second to a year.
The extra seconds are introduced every two or three years. In fact, the last one was inserted just 18 months ago in June 2015.
So what exactly is a leap second?
The
adding of the leap second is to ensure that time based on the Earth’s
rotation does not lag behind time kept by atomic clocks.
The
extra seconds are occasionally necessary because of unpredictable
changes in the speed at which the Earth turns on its axis. They are
introduced in the last minute of either December or June, or rarely
March or September.
NPL, based in Teddington, London, is the UK’s national measurement institute and the birthplace of atomic time.
Peter
Whibberley, a senior research scientist with NPL’s time and frequency
group, says: “Leap seconds are needed to prevent civil time drifting
away from Earth time.
“Although
the drift is small – taking around 1,000 years to accumulate a one-hour
difference – if not corrected it would eventually result in clocks
showing midday before sunrise.”
The
International Earth Rotation and Reference Systems Service, based at
the Paris Observatory in France, tracks the Earth’s rotation and
announces when a leap second is needed roughly six months in advance.
However,
leap seconds can cause problems for communication networks, financial
systems and other applications that rely on precise timing and has to be
programmed into computers to avoid mistakes.
It
is also possible for a second to be removed from the UTC (Universal
Co-ordinated Time) timescale, although this has never happened.
Source: giphgy.com
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