Companies around the world are bracing themselves for chaos as world timekeepers prepare to add a leap second to global clocks tonight. 

Immediately before midnight, the world clocks will officially read 11:59:60 for one second to allow the Earth's rotation to catch up with atomic time, a rare occurrence which happens every few years. And while it is good for scientific reasons, it could prove catastrophic in other mediums--specifically for airlines, technology companies, and trading floors. 

This isn't the first leap second which has caused problems. According to The Daily Telegraph, when the last leap second was added in 2012, Mozilla, Reddit, Foursquare, Yelp, LinkedIn and StumbleUpon all reported crashes, while the Linux operating system and other programs written in Java also encountered problems. In addition, more than 400 flights in Australia were grounded when the Qantas check-in system crashed.  

Experts in Britain have warned foreign markets that if their software is not prepared, that they could suffer transaction delays as a result tomorrow.  

"There are consequences of tinkering with time," peer Whibberley, Senior Research Scientist in the Time and Frequency group at Britain's National Physical Laboratory said. "Because leap seconds are only introduced sporadically it is difficult to implement them in computers and mistakes can cause systems to fail temporarily." 

The change is expected to hit trading floors in the US, Japan, Australia, South Korea and Singapore. 

The reason for the addition is to ensure civil time does not drift away from time based on the Earth's rotation, which is gradually slowing down daily. If a leap second was not added, a drift could eventually result in clocks showing the middle of the day occurring at night. 

Tags: Leap Second