Enjoy the extra second in your day – make it count

An extra second will be added to today’s length, making Tuesday 24 hours and one second long.

The move is often used by international timekeepers to keep up with tiny alterations to the Earth’s spin. This represents only the 26th second that has been added since the practice began in 1972 – however, it may also be the last.

It has been known for some time that the Earth’s rotation is gradually slowing down. Because of this, the natural or “solar” day is getting longer each year. To compensate for this, official timekeepers need to add a second to days to make sure our atomic clocks – the most accurate measurements of time humanity has – are synchronised to this solar day. If we did not use leap seconds our atomic clocks would become two minutes fast by 2100, according to the UK’s National Measurement Office.

Although the addition of the extra second will be insignificant to many, the previous leap second in June 2012 wreaked havoc online; popular websites such as Reddit and LinkedIn slowed to a halt.

In an echo of the “Y2K” fears of the late 1990s, Australian airline Qantas had to switch to manual bookings after its online system failed entirely.

Since this year’s leap second will occur on a work day, there are now concerns that computerised micro-transactions worth millions may be lost in the international stock market as countries experience the delay at different points.

Because of these complications, official timekeepers the world over have suggested abandoning the idea of leap seconds entirely.

Announcements opposing leap seconds were made by China, Australia, Japan, and South Korea at a special meeting of the Asia-Pacific Telecommunity earlier this year.

However, a UK-based roundtable found last year that more than 60 per cent of the British public supported keeping the extra second, arguing that various social and cultural issues would be affected, as well as arguing that computer scientists could easily come up with a solution.

Some companies such as Amazon and Google choose to "spread" the extra second over the course of a day to prevent any such problems.

For the moment, leap seconds will continue to be added when needed until at least 2020.

Nonetheless, the international community will debate whether to keep our notion of a solar day – which includes leap seconds – as the “official” day at a special conference in November.