Leap Second

The next leap second is almost upon us! It is due to be added at the end of this month when at midnight June 30 2015 the clocks will be wound forward by one second. This occasional adjustement is to keep Coordinated Universal Time (UTC) within an acceptable margin of error (approximately 0.9s) of Earth’s rotational time AKA mean solar time.

As harmless as this sounds it is very much the opposite given the rise of computing applications requiring very precise time keeping, financial and scientific applications in particular. This “harmlessness” was clearly demonstrated by the wide-spread commotion caused by the previouse leap second.

It gets even more complex when you consider that that the Earth is constantly decelerating due to the gravitional tug of the moon. Which is currently adding about 1.4ms per day per century and whilst slow this affect will compound over time until a leap second will be needed every day!

More complexity is introduced when telling time due to the implicit assumption it includes information about the event in time and as well as it’s location. As evidenced by the numerous time-zones and daylight saving shenanigans around the worldd. On top of this, there is also the affect that politics can have on time which can result in a country anywhere from 3 minutes to a whole day.

Who would have guessed something as boring as time could be so hard?