The Paris Observatory will add a leap second to clocks to allow Earth's rotation to catch up with atomic time, a potential headache for software companies.
The last leap second was added in 2012, causing crashes in some search engines, and problems in Linux-based systems and programs written in Java. The first leap second was added in 1972, and Jun 30 will be the 26th time one has been added.
Britain's Telegraph newspaper reports that Mozilla, Reddit, Foursquare, Yelp, LinkedIn and StumbleUpon all reported crashes with the 2012 change. Qantas' entire computer system went down for hours, forcing employees to check in passengers by hand. Google has readied itself for the April extra second. The search engine's special technique gradually adds milliseconds to its system clocks prior to the official arrival of the leap second.
The International Earth Rotation Service based in France tracks the planet's rotation and tweaks time where necessary. Scientists explain that atomic time - Coordinated Universal Time (UTC), the world's benchmark time standard - is constant, but the Earth's rotation is gradually slowing down by around two thousandths of a second per day. In some years the Earth runs bang on time and no adjustment is needed.
Date written/update: 2015-04-15