Leap second?  Just a second . . .

Leap second? Just a second . . .

Atomic Clock

Maybe it’s George McFly with this atomic clock . . .

International debate regarding the leap second continues

Unlike our ancestors, we no longer need look to the sky to get an idea of what time it is. For most of us, we reach into our pockets and grab a smartphone, or maybe twist our wrist to look at our Apple watch, trusting that it will give us an accurate time. Or perhaps one might be in a public space equipped with a large LUMICHRON clock. A quick glance at LUMICHRON’s website will reveal that many of our products are GPS equipped, coordinating our clocks to the Atomic Master Clock at the U.S. Naval Observatory. This is the same time system under which the U.S. Government operates, as well as your smartphone.

UTC and Atomic time

Atomic time is based on the frequency of oscillations of a cesium atom, and has nothing to do with the rotation of the earth around the sun. However, the international time standard, called Coordinated Universal Time, or UTC, has a solar day for its unit of duration and can differ from atomic time by an integral number of seconds.  Just as time is manipulated via regular daylight savings and leap year adjustments, UTC is also manipulated via a little known concept called a “leap second”.

The leap second, however, is not systematic. Because the movements of celestial bodies including the earth, moon, and sun are prone to variation, the addition of leap seconds is an irregular, somewhat unpredictable practice. Adding a single second every few years or so may seem insignificant, but  it can wreak havoc on networks that are integrated with UTC, such as websites, air traffic control, and power grids, whose coding must be adjusted manually to account for the difference.

The problem of leap seconds is now under debate internationally, and a vote is scheduled for June of this year. Time and its measurement are determined by a very complex system involving astronomers, physicists, and international organizations around the world. The standard time broadcast by all countries around the world is controlled to at least 1/1000 of a second.  In fact, time is controlled to within a very few millionths of a second!

Atomic time is simply too accurate for earthlings.

The most recent adjustment for a leap second was June 30, 2012. As Wired reported, “Earth’s official time keepers held their clocks back by a single second in order to keep them in sync with the planet’s daily rotation, and according to reports from across the web, some of the net’s fundamental software platforms — including the Linux operating system and the Java application platform — were unable to cope with the extra second.”  Just hours later though clocks and systems had been adjusted to accommodate the extra second.

Even though it might take centuries for time to be off by even an hour if leap second adjustments were abandoned, time has been defined by the Earth’s rotation for over 5,000 years.  So shouldn’t clocks be adjusted to the Earth’s rotation?  Or should atomic clocks be solely responsible for measuring time?