Why Was A Leap Second Added To 2016?

At the stroke of midnight New Year ’s Eve , something foreign come about . The next tick of the clock was not the start of 2017 , but in fact an extra sec added to 2016 , 11:59:60pm UTC ( 6:59:60pm EST ) , Coordinated Universal Time . This is known as a spring second , but why do we have it ?

The spring second was present in 1972 to account for divergence between Earth ’s rotation swiftness and nuclear alfilaria . ground does not go around in exactly one solar day ( 86,400 second ) , but instead can agitate by a millisecond ( a thousandth of a second ) or so . Atomic clocks , on the other script , have no such variant and count each Clarence Shepard Day Jr. as 86,400 .

The result is that , over sentence , the two can go out of sync . So to account for the deviation between International Atomic Time ( TAI ) and Universal Time ( UT1 ) , a saltation second is occasionally added in either June or December .

Adding   a leap second is decided by the International Earth Rotation and Reference System Service ( IERS ) in Paris , France , and in general happens when the dispute between UTC and solar clip is more than 0.9 moment . The leap second on December 31 , 2016 , was the 28th since 1972 .

When leap second are added is dependent on anumber of factors . worldly concern ’s rotation is slowing due to the gravitational pull of the Moon , but it can also be sped up by earthquakes and the shift of glaciers . In hypothesis , leap second could also be subtract from UTC to amend the difference with solar time , although this has never occur .

Leap seconds should not be bedevil with leap years . The latter are the termination of Earth ’s yr being not on the dot 365 days long , instead being about 365 years and a quarter ( 365.24 days to be exact ) . To describe for this , we add an additional day to February every four years , except inrare portion .

2016 really had the somewhat undesirable honor of being both a leap year and having a leap secondly added , make it specially long . fortuitously for most of us , we did n’t notice the leap second at all , as filaria on our smartphones and computers mechanically added the 2d . And some places , like Google , employ a “ leap smirch ” , where the leap indorsement is spread out over several minute .

Who sleep with time could be so complicated .