However, the rotation speed of the Earth fluctuates unpredictably, and has been found to even slow down due to friction caused by the ocean tides -- hence the need for a leap second
The Emirates Metrology Institute (EMI) has announced that a leap second
will be added to UAE standard time just before 4am on July 1 when clocks will read 03.
It has made an announcement that one leap second
would be added to June 30, 2015, and the clocks would read 11:59:60 p.
The so-called leap second
was added to electronic clocks at midnight universal time on Saturday, with atomic clocks reading 23 hours, 59 minutes and 60 seconds before then moving on to Greenwich Mean Time.
Confusion sometimes arises over the misconception that the regular insertion of leap seconds
every few years indicates that the Earth should stop rotating within a few millennia.
Timekeepers argue that both measures are useful but haven't agreed when to add leap seconds
to make the planetary and the atomic clock years match up (SN: 4/22/06, p.
It's not as if professional astronomers couldn't make the necessary corrections, Seaman adds, but abandoning leap seconds
would be a complicated and expensive proposition.
have been occurring since 1972 in either January or June - every one to seven or so years as needed to maintain Earth, not man-made clocks, as the ultimate timekeeper, said John Mosley, an astronomer at the Griffith Park Observatory.
were introduced in 1972, but this is the first to be used for seven years.
Such leap seconds
are announced typically five months before they take place.
So if the artifact that constrains seconds to the range 0 to 59 is integrated with any that propagate leap seconds
, it might fail all of a sudden one New Year's.
From the offset date, dates and times were represented as floating-point atomic (TAI) minutes from the offset, thus avoiding the annoying leap seconds
that occur in universal time (UTC).
However, civilian time contains leap seconds
inserted as needed to keep it matched to the Earth's observed rotation.
Originally, leap seconds
were added to provide a UTC time signal that could be used for navigation at sea.
The International Earth Rotation and Reference Systems Service (IERS), based in Paris, is responsible for keeping track of the gap between the precise-atomic clock and the planetary time and deciding when to make additional leap seconds