How 2015 Will Gain a Second in Time

The Paris Observatory, home of the "Lords of Time," as they are often called, has determined that on June 30 of this year, all clocks will be asked to "hold their breath" for a single second so that Earth's rotation can catch up to the digital read. So why exactly do we have to do this? And just what is a "second" anyways?

Time has always been a pretty obscure concept, as it is more of a manmade illusion - a point of reference - than anything else. For many individuals, time can be best understood by the progression of "happenings," which will come to a grinding halt the second they go into a coma... at least until they wake up to find a robot nurse and flying cars whizzing outside a nearby window.

Then they will find themselves thinking, "man, a lot of time must have passed."

But time is a much more quantifiable thing too. We see it on clocks, and for many regions, those clocks were all based around the same standard: when the Sun comes up and when it sets. Greenwich Mean Time (GMT), which is measured by the time at which the Sun crosses the Greenwich Meridian and was adopted in Britain in 1847, is a relatively fixed point for standard time. This is why you can always look up how to convert GMT to your time zone, making planning a trip to Europe a little easier for world travelers.

In fact, that's why there's a standard time and such a conversion system at all - where schedules for trains and planes need to be timely based around a shared international something.

And that something, it turns out, is the second. The second is the basic building block of humanity's rather archaic time system and for the last several decades, experts have been tacking on a second here and there in order to keep the idea of a "day" synched with the Sun.

And no, this has absolutely nothing to do with "daylight savings time," which is actually a political affair inspired by wartime efforts and does not change the length of an overall year. Adding a second to a single day in a year, however, makes it a little longer. (Scroll to read on...)

So why do we do it? Unlike the second, which is conceptually constant, the rotation of the Earth is changing. To compensate for this, experts at the Paris Observatory have been playing with time.

"The Earth is slowing down a little bit," Nick Stamatakos, the chief of Earth Orientation Parameters at the United States Naval Observatory, recently explained to The Telegraph. "Atomic clocks keep very accurate time. The measurements are telling us 'Oh, they're slowing down.'"

He went on to explain that Paris added its first leap second in 1972, and have since done it 24 more times.

But what's this about atomic clocks? How can they know that the Earth's rotation is slowing? These questions take us straight back to the second - that fundamental building block of "time."

If minutes, hours, days, and years are all made up of seconds, it's very important that no matter where you are in the world, or even the Universe, the definition of the second stays constant. Otherwise we'd never be able to properly convert time for travel. And nothing could be more constant than another universal building block: atoms.

An atomic clock then, is not a radioactive mechanism. Instead, it measures oscillations much like a standard mechanical clock. If you were to look closely at your watch, the second hand ticks by based on the oscillations of mass on a spring, which in turn drives the movement of gears. That's the tick tocking that we often hear.

However, springs wear down, and a clock can slow. Not so in the case of the atomic clock, which measures seconds by the oscillations of electrons around cesium atoms. Since 1967, the official definition of a second is 9,192,631,770 cycles of cesium vibrating between two energy states, and physicists are fairly certain that nothing can be more constant.

So rejoice! Come June, you will gain 9,192,631,770 electron cycles to your day! Could anything be sweeter? Probably... yes... absolutely... but it's a nice tidbit of knowledge all the same.

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