Nanogirl Michelle Dickinson: What will you do with today's extra time?

Though slowing overall, the Earth's rotation has also been found to speed up following some earthquakes. Photo / 123rf

Opinion

If you need a little extra time to complete last year's New Year's resolutions, then this might be the year for you - 2016 is going to be a whole second longer, with a "leap second" being added to December 31 to compensate for the shifting rotation of the Earth.

The Earth's rotation is slowing slightly with time, caused in part by tidal effects, with the Moon's gravity creating friction between the oceans and the turning Earth.

In the 1800s, a day was defined as 86,400 seconds; today it is around 86,400.002 seconds.

Interestingly, while slowing overall, the Earth's rotation has also been found to speed up following some earthquakes, as the planet's mass is redistributed.

The fault that triggered the 8.9 magnitude Fukushima earthquake in 2011 moved Japan's main island by more than 2 metres - this shifted the Earth's figure axis by about 17 centimetres, which shortened the length of the day by 1.8 microseconds.

The 2004 Sumatran earthquake similarly shortened the day by 6.8 microseconds.

The International Earth Rotation and Reference Systems Service (IERS) is responsible for keeping clocks synchronised with the Earth's movement in space, determining when the addition of a leap second is required to maintain alignment.

Measuring the Earth's rotation in their Paris-based observatory, they monitor 400 highly precise atomic clocks positioned all around the world, and work to keep the Co-ordinated Universal Time (UTC) in check.

The IERS announced back on July 6 that a leap second was needed this year.

Leap seconds typically occur every two or three years, with 26 leap seconds having been added since the practice began in 1972.

That first year, we got 10 leap seconds all at once to make up for lost time.

Though needed to keep atomic time in sync with astronomical time, the implementation of leap seconds can cause challenges with software, as computer systems struggle to cope with a 61 second-long minute.

When the last leap second was inserted in June 2015, glitches in software were reported around the world as computers struggled to interpret the change in time, and so lost synchronisation with one another.

With so many critical applications nowadays dependant on precise timing to interact - communication networks and financial systems as key examples - this can create real problems.

Some of the world's biggest technology companies are considering ways to better ensure software sychronisation and protect against these challenges.

Google will this year be sharing "Smeared Time" with the world.

This unique unit of time was created by Google specifically to help online software systems cope with the extra second.

Google's Network Time Protocol (NTP) - a clock shared across the Internet for systems to reference - will run the clocks 0.0014 per cent slower across the 10 hours before and 10 hours after the leap second.

This "smears" the extra second across 20 hours, so the software can compute December 31 just like any other day.