TECH
30/06/2015 07:24 BST | Updated 30/06/2015 07:59 BST

What Is A Leap Second? This Chronological Mystery Explained

The planet Earth is slowing down. This has made everyone incredibly annoyed.

The Earth's gentle braking means that at midnight tonight the world will have to get a leap second. Could this vital addition prove to me more trouble than it's worth? What even is a leap second? Should I start building a bunker?

moon orbit

What is a leap second?

It's a glitch in the world's chronological order, and yet it's utterly essential. As the Moon acts as a giant brake pad on the Earth's rotation, the world begins to move out of sync with the over 400 atomic clocks that make up our version of 'time'.

We need this extra second to bring us back in sync with the Earth's rotation and thus maintain our perfect system.

In the past it was never really an issue because in truth, we weren't very good at telling the time. Well now we have atomic clocks, and despite the fact that we have a 0.9 seconds of wiggling room, that wiggling room is about to run out.

What would happen if we didn't have a leap second?

At first, nothing. Gradually over time (around 800 years) however, the Earth's rotation would decrease to such a degree that the Sun's highest point would be at 1pm instead of noon.

Now that might seem like a very very gradual change, but an hour's difference would have monumental effects on how we as humans organise our lives. Everything we did would be out of sync.

Who Decides If We Have The Leap Second?

So who can we blame for this inconvenience? A number of people, however the main perpetrators are the scientists at the International Earth Rotation & Reference Systems Service based at the Paris Observatory.

From there they coordinate with the National Physical Laboratory in the UK and over 400 other atomic clocks which combined make up the Coordinated Universal Time or UTC.

atomic clock

Over 400 atomic clocks like this one at the NIST in the US help define 'time'.

This universal time is then closely monitored in relation to cosmic events which could in anyway alter the speed with which the Sun passes over the sky.

Because of the nature of these events it's not always immediately clear if they actually need to happen so the ERRSS can only really give the world around six months notice for a leap second.

So Should I Be Worried About The Leap Second?

No, but that doesn't mean there won't be problems. Six months is not a lot of notice for the entire planet and many software systems won't be updated in time which means that huge companies will need to update their systems manually.

That's where things go awry. Last time it happened Qantas literally shut down due to a programming error while various websites crashed.

While it's impossible to predict exactly what'll happen there could be disruption to some technology and your apps as each of the developers will need to update their own software manually.

It also has some rather worrying implications for the global markets as this is the first time a leap second has been introduced manually to a completely electronic market.

This, combined with the current financial crisis in Greece, has got some people worried about what might happen to the markets. Of course again the problem is that it's almost impossible to predict.

So should I start building a bunker?

No. Though you might want to consider buying a pocket watch.