TIME will stand still today - delaying midnight by a second.
An extra sliver of time - a "leap-second" - is being added to the world's clocks to adjust for the inaccuracy of the spinning Earth.
Before the invention of super-accurate atomic clocks, time was based on the Earth's rotation, one complete turn taking 24 hours.
Now a plethora of time-sensitive systems, including computer programmes and financial markets, rely on the precise ticking of atomic clocks that measure the energy transitions of atoms.
The problem is that due to the moon's gravity the Earth is slowing down, and not in a regular way. So every now and then a leap second is added to allow astronomical time to catch up with atomic time. It is similar to the introduction of leap years keep our calendars lined up with the Earth's orbit around the Sun.
The latest pause - the 26th - will occur tomorrow, June 30, at 23:59:59 co-ordinated universal time (UTC), which is an hour behind British Summer Time. UTC provides a world-wide time standard free of time zones.
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