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The addition of a leap second is more important than you think

There’s been a lot of media coverage about this evening’s leap second and why it’s happening. For the short and sweet, we thought we’d let Neil deGrasse Tyson do the explaining. But there’s a lot more to this story and that’s where things get interesting.

All of our seconds during the day are accounted for — so for one second following the stroke of midnight this evening time will technically stand still and the leap second occurs. It may seem innocuous, but it is quite honestly anything but.

Interestingly enough, there’s actually a lot of controversy surrounding these rather tiny time changes. They cause rather significant problems for software. In fact, after the most recent insertion of a leap second in 2012 (seen below), a number of major websites experienced software problems, including Qantas Airways Ltd., Reddit Inc.Leap Second on official US Government clock, and a number of major systems running on Linux. GPS satellites and ground-based receivers also experienced problems as the systems struggled to cope with the non-conventional time addition, leaving some systems with the wrong time. And last, but certainly not the least, are the serious concerns with how the financial markets will handle the insertion of another second. This may sound silly, but don’t forget that with high frequency trading systems, a second can be a lifetime.

According to Bloomberg, one second means…

  • 1.4 million — Order messages sent to U.S. equity-trading venues
  • $4.6 million — Amount of stocks traded every second all day around the world
  • $3.7 billion — Amount of stocks changing hands at the bell in Korea, Japan and Australia

“Hundreds, if not thousands, of firms around the world now trade everything from stocks to junk bonds to interest-rate derivatives electronically. The fastest of them has the ability to react in millionths of a second. To lessen any possible impact of the leap second, NYSE Arca Equities said evening trading will close five minutes early; Nasdaq will stop trading at 7:48 p.m. New York time and shut down at 7:55 p.m.; Intercontinental Exchange Inc. said it’s delaying all market transitions; CME Group Inc. said any data files submitted between five minutes before and after the leap second will be held for processing till five minutes after. The extra second is coming amid a critical week for global investors, with Greece’s debt crisis worsening. June 30 is the day when the nation’s current bailout is set to expire and when a payment to the International Monetary Fund is due.”

And as Geoff Chester, public affairs officer for the U.S. Naval Observatory in Washington, explained, roughly 10 percent of large-scale computer networks will experience technical difficulties in dealing with the leap second.

So the ultimate question is — what will you do with your extra second? Let us know.


  1. Mike Mike June 30, 2015

    I think I’ll celebrate with really small glasses of champagne!

  2. Ralphi Ralphi June 30, 2015

    An extra second of sleep!

  3. NerdyCat NerdyCat June 30, 2015

    um, probably sleep… I know I’ll be excited to watch the clock change and then just fall asleep right before it happens

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