One giant leap (second) for 2016

If you can’t shake the feeling that 2016 went on for longer than a typical calendar year, you’re not actually far from the truth.

In addition to being a leap year, 2016 saw the introduction of a ‘leap second’ immediately before midnight on 31 December UTC (Coordinated Universal Time) to account for a very slight slowing in the Earth’s rotation. Here in Australia, the extra second was formally added to atomic clocks at the National Measurement Institute (NMI) immediately before 11 am AEDT on New Year’s Day.

The need for a leap second is determined by the International Earth Rotation and Reference Systems Service (IERS). The IERS keeps track of time by comparing the Earth’s rotation, which varies, against an international network of atomic clocks. Introducing the leap second keeps the time difference between the two ‘clocks’ to below 0.9 seconds; without leap seconds being added periodically, calendar time and atomic time would gradually drift apart.

Although minor, the leap second will impact the daily life of many Australians, with the NMI’s timing systems linking the atomic clocks to areas such as industry, defence, government, law enforcement, telecommunications and financial markets. So whether you’re trading shares, using a GPS, catching a train or even watching sport, you can be thankful for the work of the NMI and the leap second for keeping you in tune with the rest of the world.