June 30 the world will get an extra second – Focus

The leap second was added on a regular basis usually in December or June since 1972. All this in order to synchronize the time universal with an average sunlight. In recent years, leap seconds, have become less regular, and the last an extra second was added June 30, 2012, at: 23:59:60 UTC. Why is that?

– Earth’s rotation gradually becomes slower, and the extra second is the way to this level – explains Daniel MacMillan of NASA’s Goddard Space Flight Center.

The International Earth Rotation Service and Systems References International Association of Geodesy decided to add a leap second in January this year.

Time earthly and UTC time

Strictly speaking, the day lasts 86,400 seconds. At least if its length is measured using UTC time, in which the length seconds cesium atoms measure the impact. Their behavior is so predictable that the accuracy of an atomic clock is 1 second at 1.4 million years. [Read more: HOW DOES THE ATOMIC CLOCK?]

Less accurate is the time the earth, which is based on how long the Earth rotates around an axis. This usually takes approx. 86400.002 seconds. That’s because the Earth rotates more slowly, among others, due to gravitational interactions between the Earth, Sun and Moon and the movements of magma and in the interior of the planet. At the rotation of the Earth also affects the atmosphere, earthquakes and many other factors. The turnover of our planet are changing at different rates. Scientists estimate that “the day the earth” last time took 86,400 seconds approx. 1,820 years!

By 1967 odmierzaliśmy world based solely on observations of the sun in the sky. In 1972, he introduced UTC or Coordinated Universal Time, which is based on atomic clocks (time to time shall be adjusted manually). Leap second to coordinate terrestrial time to UTC.

Changing the June 30, 2015 will take place around the world at the same time and take into account the division into zones. Leap second will be added exactly 30 June at. 23.59.60. This means that, according to the UTC last minute of the last day of June 2015, it will lasted exactly 61 seconds.

In our zone CEST extra second will fall on 1 July at 01.59.60.

Additional second and electronics

The leap second is unlikely to be noticed by people. But how to react computers and other electronic devices? Changing the time can be a threat to computers that use NTP Network Time Protocol. It allows time synchronization between different devices to the nearest tenth of a second.

The last such jump has caused considerable problems – some large websites were inaccessible (such as Linkedin service), passengers Australian airline Qantas could not board the aircraft. All because some computer systems did not lift time in the format 23:59:60.

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