The international agency that monitors Earth's rotation has announced that 2015 is scheduled to last a little longer – by one second!Paris
As announced by the International Earth Rotation Service at the Paris Observatory, a leap second will be added to standard universal time at 11:59 p.m. on June 30. The addition will correct the discrepancy that has accumulated in recent years between astronomical time, which is calculated based on the Earth's rotation, and the so-called "Synchronized Universal Time" (UTC), a standard based on measurements from atomic clocks around the world.
Atomic clocks measure time at a perfectly constant rate, while astronomical time exhibits small deviations. A variety of factors, such as the gravitational interaction of the Earth with the Moon, vary the speed of the planet's rotation and therefore the length of the 24-hour day.
Theoretically, the Earth's rotation speed could increase, in which case a negative leap second would have to be added to the universal time. However, this is rare. The usual practice is to add positive seconds, since in recent decades the Earth's rotation period has tended to decrease by about 2 milliseconds per day.
Abolition;
Leap seconds have been added a total of 25 times since the measure was first implemented in 1972, five years after the definition of the second was changed to be based on atomic time rather than astronomical time.
Today, the US and other countries are calling for the elimination of leap seconds because of the problems they cause to Internet infrastructure and GPS satellites. The addition of the last leap second in 2012 brought websites like Reddit, LinkedIn, StumbleUpon and Foursquare to their knees, while problems also appeared in the Linux operating system and programs written in the Java language.
Google was prepared for the change thanks to a software upgrade called “leap second.” Essentially, the upgrade adds several extra milliseconds before the official leap second arrives so that the change is not abrupt. Because of the potential impact on computing systems, the U.S. now wants to eliminate leap seconds altogether.
Disagreements
Other countries disagree, as abolishing the measure would mean that the international time standard, UTC, would be disconnected once and for all from astronomical time based on the Earth's rotation. Among the countries that are reacting is Britain, as abolishing leap seconds would effectively abolish Greenwich Mean Time, the astronomical time measured at the Earth's prime meridian near London.
Greenwich Mean Time is practically the same as UTC, but it has a different definition and is officially used less and less. As Rory McEvoy of the Royal Observatory in Greenwich said, whether to keep or eliminate leap seconds has been the subject of passionate debate for 12 years. A final decision could be made this year at the World Radiocommunication Conference, which will be held in Geneva in November.
