During the first week of January, 2015, the International Earth Rotation Service (IERS) decided that this year on June 30, an additional second would be added to our time measurement here on Earth. The leap second is added to the coordinated universal time (UTC), the international standard time for civil use.
The addition of the leap second could potentially wreak havoc on some computer systems and websites not equipped to handle the change. This very thing happened on June 30, 2012, the last time we gained a leap second. Yelp, Linkedin, and Qantas had some issues related to the added second.
Amazon Web Services has already announced their plans for the event, saying they will “implement alternative solutions to avoid the ‘:60’ leap second. This means that AWS clocks will be slightly different from the standard civil time for a short period of time.”
They actually could have chosen December or June says the IERS. Since the leap second was implemented in 1972, we have gained 25 seconds and lost nary a one, and if you wonder why these leap seconds are necessary, you won’t get a definitive answer from the IERS in Paris, France.
Just what is UTC or “coordinated universal time?”
The expression, coordinated universal time, or UTC is a 24-hour time standard that is the basis for “civil time.” This time is kept using an atomic clock combined with the Earth’s rotation. So UTC is used by just about every country in the world. This allows us to all have the correct time in our particular time zones.
But understand, UTC time has nothing to do with time zones, being that it is a standard that keeps the world’s time centers synchronized. As an example, as I sit here writing this story, it is 3:25 p.m. EST on my computer. Looking at the website that gives the UTC time, it is 7:25 p.m. The UTC time is recognized all over the world, and adjusted to the particular time zone.
There are two components that make up UTC. One is the International atomic time (TAI). This time scale uses information from 200 atomic clocks around the world to provide the exact speed our clocks tick. The second component of UTC is called Universal time (UT1).
UT1 is sometimes called solar time or astronomical time and refers to the Earth’s rotation. So now we have explained the two components that make up UTC. Let’s see what this all means. UT1 or universal time is used to compare the actual speed of the atomic clocks (TAI) with the actual length of a day on Earth.
Scientists have known for a long time that the rotation of the planet has been slowing, although it is not perceptible to us. This slowing of the Earth’s rotation is important in determining the length of a day. At the same time, the TAI is equally important when it involves time-sensitive instruments, such as those used in air-traffic control.
Why do some scientists think we don’t need leap seconds?
Peter Whibberley, of the National Physical Laboratory in Teddington, UK says atomic clocks keep better time than the Earth itself. “Previously the Earth was the ultimate reference and man-made clocks were adjusted to match,” says Whibberley.
“From the beginning of the 1960s, atomic clocks became the ultimate reference. They were adjusted to keep in step with the Earth. Then, in 1972, it was decided that instead of adjusting how fast the clocks ticked, they would be left to tick away at the atomic rate and the leap second would be introduced.”
Right now, leap seconds are causing problems with technology. In 2012, 400 Quantas flights were affected by the leap second. Some people have suggested just adding a minute every so often while countries like the U.S., France, Mexico, and Japan want to end leap seconds altogether. They suggest doing away with leap seconds and letting the atomic clocks just run away. When all those leap seconds make an hour, then either move all the clocks forward an hour or back an hour.
But one second can be important. In one second, one billion dollars can be transferred to an off-shore bank account. In one second, a satellite can go seven kilometers through space. Is that leap second important to you? Don’t blink.
