One extra second will be added to earth time on June 30 as the earth rotation experiences a gradually slowdown. The International Earth Rotation and Reference System Service (IERS), a body responsible for administering global time, has fixed June 30 as the day to add in the extra second to compensate for the gradual slown down rate of the earth's rotation. That means the last minute of June 30 will have 61 seconds instead of 60 seconds.Mohd Zamri Shah Mastor, a science officer under the Ministry of Science, Technology and Innovation, explained that a "leap second" is nothing new because IERS reported that it had happened 25 times since 1972.