Did you know that 2015 will have an extra second? This is called a “leap second”. At 23.59 on Tuesday the 30th of June, clocks will count all the way up to 60 seconds showing 23:59:60 before rolling over to 0:0:0 on the 1st of July. This will allow the Earth’s natural rotation speed to catch up with atomic time.
The Earth’s spin is gradually slowing down, caused by the strong gravitational pull between the Earth and the moon, making each day about two thousandths of a second longer than the last. The atomic clock, however, is absolutely accurate. So occasionally years have to be lengthened to allow the two to synchronise.
Leap seconds can wreck havoc across the internet and with computer, server and navigation systems. Anticipating the problem, Google has created a solution called the “leap smear”. It has modified its internal servers to add a few milliseconds every time they are updated, so that when the leap second occurs they will have already caught up with the new time.
So hopefully everything will run smoothly on the 1st of July. A day usually has precisely 86,400 seconds; so at least on Wednesday morning you can enjoy one more second of sleep!