The day before New Year 2017 will officially be one second longer for everyone on Earth as a "leap second" will be added this year on Dec. 31 at 23 hours, 59 minutes and 59 seconds, Coordinated Universal Time, which is 6:59:59 p.m. EST.
What Is A Leap Second?
All spatial objects including stars, planets, moons, asteroids, and comets demonstrate certain unique characteristics. The Earth performs dual motions that include rotation (around one's axis) and revolution (in one's orbit). The Earth's rotation is the key factor behind the concept of a leap second.
A leap second is the time added by the world's timekeepers then and now on either June 30 or Dec. 31. This event is necessary to keep clocks synchronized with the Earth's consistently slowing rotation. It is a well-known fact that our planet completes one full rotation in 24 hours, but in reality it takes a little longer than that - 86,400.002 seconds to be exact, noted Vox. Therefore, a leap second is added every few years to the world's official clocks.
The concept of adding a leap second was initiated in the year 1972. Since then the International Earth Rotation and Reference Systems Service has been adding a leap second for the past 27 out of 44 years. The last time a leap second was inserted was on June 30, 2015.
How Does One Extra Second Affect You?
An extra second added every few years hardly seems significant, but it is required to keep up the time reflected in atomic world clocks with the Astronomical Time, which refers to the time taken by the Earth to rotate around its axis.
"The worldwide coordination of time signals is critical for the functioning and reliability of systems that depend on time," said François Rancy, ITU Radiocommunication Bureau director.
"With GPS, for example, time is measured in billionths of a second. Not taking into account something as long as a leap second would result in a 1/5 mile error at the equator," explained Cliff Minter, an analyst with the National Geospatial-Intelligence Agency's GPS Division.
People do not have to do anything to make their clocks keep up with the one-second change as electronic devices such as computers, phones, and tablets that automatically set their time will adjust and add the one second on their own. As for the other clocks requiring mechanical interference, the difference of one second will be too small to notice. What to do with your extra second? Get a few ideas from onesecond.wtf.
Why Is Earth's Rotation Slowing?
The Earth's movements cause some spectacular spatial phenomenon such as the lunar eclipse and solar eclipse. As assumed by many, the Earth's rotation around its axis is not fixed and steady. Instead, it is continuously varying and slowing down with time.
The main reason behind the Earth's unsteady rotation is the movement of the ocean tides. As the planet rotates, it turns over a great watery hump, usually formed by the gravitational interfacing of the Earth and the moon. The bulge tends to slow down the motion, similar to a brake on a rotating wheel.
The slowing down of the Earth's rotation is a gradual phenomenon. According to sources, after one day, it is 0.002 seconds. Adding up the time for about one year and a half, the difference comes up to be about one second. Hence, there comes a need to add one leap second to the world's time every one and a half years.
