It’s Leap Second Day! Time to Get in Sync
http://gpsworld.com/its-leap-second-...o-get-in-sync/

“Time waits for no one,” Mick Jagger lamented in song when he turned
30. But tonight, on the evening of June 30, our clocks will stand
still for a moment, waiting for the passage of a “leap second.”

The International Earth Rotation and Reference Frames Service (the
world’s time monitor) has decreed that the last day of June will
contain an extra second. Rather than the usual 86,400 seconds in a
day, June 30 will have precisely 86,401 seconds.

National time-keeping centres around the globe, such as the National
Research Council in Ottawa, will insert this extra second or leap
second into their master clocks so that they remain synchronized with
an international time standard. All other clocks that get their time
from a master clock will be updated similarly. This includes all of
the so-called time servers on the Internet, which keep our computer
clocks in sync.

This global time standard is called UTC or Coordinated Universal
Time. The standard was established in the 1960s once it was
demonstrated that the newly developed atomic clocks could keep time
with unprecedented precision and that clocks, even if they were on
different continents, could be synchronized with each other to a
fraction of a microsecond.