Today, on June 30, 2015, a leap second will be added at the end of the day.

The IERS (International Earth Rotation and Reference System Service) organization announced the planned adjustment of the Coordinated Universal Time UTC by the insertion of a leap second to the last minute on 30 June 2015. In our country, this event will take place on July 1, 2015 at 1h 59m 59s local time.

We have staged this phenomenon on the atomic clock at our Laboratory of the National Time and Frequency Standard and you can watch it on the video below.




The first leap second was added in 1972. This year's leap second will be the 26th since then.

The leap second can theoretically also be removed from the day, however, it has not yet occured. 

You can also watch the Czech TV reportage here (in Czech only)




IPE carries out fundamental and applied research in the scientific fields of photonics, optoelectronics and electronics. In these fields, IPE generates new knowledge and develops new technologies.

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