London: Scientists have revealed that the year 2015 will have one extra second to compensate for the Earth's slowing rotation.

However, it is feared the 'leap second' added at midday on June 30 by scientists at the International Earth Rotation Service in Paris could spark internet crashes, the Mirror reported.

According to scientists, Earth's rotation is gradually slowing by around two thousandths of a second per day and when the last leap second was added in 2012, Mozilla, Reddit, LinkedIn and scores of other sites crashed.

Nick Stamatakos, from the US Naval Observatory, said that atomic clocks add an extra second, so the day of June 30 will have 86,401 seconds, instead of 86,400 seconds and the length of the day on the Earth will have an extra second.

Google has developed a 'leap smear' technique where it gradually adds milliseconds to its system clocks prior to the official arrival of the leap second.