Baku. 22 June. REPORT.AZ/ On June 30 at 23:59:59 GM, the world's clocks will add an extra second to the day - bringing the total number of seconds for 2015 up to 31,536,001.
Report informs citing foreign media, scientists say adding this 'leap second' is crucial to compensate for the slowing of the Earth's rotation.
But according to some computer experts, the added time could wreak havoc to systems powering the internet.
The extra second is needed because the Earth's rotation is gradually slowing down by around two-thousandths of a second per day, and it needs to catch up with atomic time.
Atomic time uses vibrations within atoms to measure time and is said to be the most reliable because atoms resonate at extremely consistent frequencies.
So leap seconds are occasionally used to help 'Earth time' catch up to 'atomic time' as the former is slower by about two thousands of a second per day.
To keep them in sync, it is necessary to occasionally jump Earth's time back - for mathematical reasons similar to adding leap years.