A leap second will be added on June 30 to adjust atomic time in accordance with irregularities in Earth’s rotation.
“Earth's rotation is gradually slowing down a bit, so leap seconds are a way to account for that," said Daniel MacMillan from NASA.
According to Coordinated Universal Time (UTC), a day lasts 86,400 seconds. UTC is also known as “atomic time,” where duration of one second is based on the activity of cesium atoms.
Computed according to the duration of Earth’s rotation, however, the average length of a day is about 86,400.002 seconds. These extra .002 seconds add up to one leap second in a year.
It’s estimated that the average day hasn’t been exactly 86,400 since 1820.
Seasonal and daily weather changes along with dynamics of the planet’s inner core can affect the length of the day.
Since 1972, twenty five leap seconds have been added, the latest on June 30, 2012.
The leap seconds are added either on December 31 or June 30. This year’s adjustment coincided with the Muslim holy month of Ramadan.
The holy month of Ramadan is celebrated by Muslims on the ninth month of every year according to the Islamic lunar calendar.
It is a time of deep reflection, sharing and refraining from materialistic pleasures from dawn till sunset for 30 days.