There’s a good reason for that.
2015 will be longer than most years. One second longer, in fact.
Earth’s rotation on its axis is gradually slowing, due to tidal drag*. A day is the time it takes the Earth to rotate once on its axis. As the Earth’s rotation slows, the length of each day becomes very slightly longer. Around two thousandths of a second longer each day.
Scientists at the International Earth Rotation Service in France have responsibility for monitoring the Earth’s rotation, & occasionally add a leap second to bring clocks back into synchronization with the Earth’s rotation.
On 30 June, an extra second will be added at 23:59:60.
http://www.smh.com.au/technology/sci-tech/extra-second-to-be-added-to-2015-as-tech-companies-brace-for-problems-20150108-12k0yk.html.html?utm_source=outbrain&utm_medium=cpc&utm_campaign=outbrainamplify
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* Why the Earth’s rotation is slowing
http://www.physlink.com/Education/AskExperts/ae695.cfm / slightly longer Paris Observatory add adding leap second clocks midnight June 30 dials 11:59:60 one second clocks pause Earth's rotation atomic clock time Earth's rotation gradually slowing scientists officials International Earth Rotation Service France monitor planet's rotation tweak time time adjustment Software companies problems last leap second added 2012 software websites Mozilla Reddit Foursquare Yelp LinkedIn StumbleUpon reported crashes problems Linux operating system programs Java computing systems Network Time Protocol NTP keep sync atomic clock programmed unexpected extra second Google developed special technique leap smear adds milliseconds system clocks leap second Earth is slowing down a little bit Nick Stamatakos chief of Earth Orientation Parameters US Naval Observatory Atomic clocks keep very accurate time first leap second 1972 rotation of the Earth slowed 26 seconds time measured on atomic clocks disruptive precision systems navigation communication concept time rising setting rise set Sun Greenwich Mean Time Sun crosses the Greenwich Meridian never be restored because /
