A leap second, the 26th, June 30, 2015 at 23:59:60 UTC

A leap second, the 26th, June 30, 2015 at 23:59:60 UTC

The International Earth Rotation and Reference Systems Service in 1972 set "leap second" phenomenon. A leap second is a one-second adjustment that is occasionally applied to Coordinated Universal Time (UTC) in order to keep its time of day close to the mean solar time, or UT1. Without such a correction, time reckoned by Earth's rotation drifts away from atomic time because of irregularities in the Earth's rate of rotation. The necessity of adding leap seconds is caused not sufficient accuracy designation in the 50s, the length of the solar day and the resulting length of a second, changes in Earth's rotation period due to unforeseeable factors, such as mass movements in the interior of the Earth, and constant deceleration speed of Earth's rotation caused by friction masses of earth and water during tidal.The most recent one happened on was inserted at the end of June 30, 2015 at 23:59:60 UTC

Berlin - Burkhard Beins
A leap second sound recorded using small steel ball rolling across the concrete ground of backyard .

Paris - Mark Baron
A leap second sound recorded on 3 simultaneous layers/focals of the same action :feld recording (binaural microphones/ tape recorder) of the "start/stop" recording process of our second made on another tape recorder, sound of this (second) tape (omni microphone/tape recorder with high recording level), headphones/ omni microphone feedback created with second recorder's playback.

Seydisfjordur - Gerard Lebik
A leap second sound recorded using victorian synthesizer inside silo in Herring Meal Factory.

https://hpiers.obspm.fr/eoppc/bul/bulc/bulletinc.49

INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS)

SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE

SERVICE DE LA ROTATION TERRESTRE DE L'IERS
OBSERVATOIRE DE PARIS
61, Av. de l'Observatoire 75014 PARIS (France)
Tel. : 33 (0) 1 40 51 22 26
FAX : 33 (0) 1 40 51 22 91
e-mail : services.iers@obspm.fr
http://hpiers.obspm.fr/eop-pc

Paris, 5 January 2015

Bulletin C 49

To authorities responsible for the measurement and distribution of time

UTC TIME STEP
on the 1st of July 2015

A positive leap second will be introduced at the end of June 2015.
The sequence of dates of the UTC second markers will be:

2015 June 30, 23h 59m 59s
2015 June 30, 23h 59m 60s
2015 July 1, 0h 0m 0s

The difference between UTC and the International Atomic Time TAI is:

from 2012 July 1, 0h UTC, to 2015 July 1 0h UTC : UTC-TAI = - 35s
from 2015 July 1, 0h UTC, until further notice : UTC-TAI = - 36s

Leap seconds can be introduced in UTC at the end of the months of December
or June, depending on the evolution of UT1-TAI. Bulletin C is mailed every
six months, either to announce a time step in UTC or to confirm that there
will be no time step at the next possible date.

Daniel Gambis
Head
Earth Orientation Center of IERS
Observatoire de Paris, France