Ladies and gentlemen, synchronize your watches.

The International Earth Rotation and Reference Systems just gave the planet the gift of time. An extra ‘leap second’ will be added to Coordinated Universal Time (UTC) at 23:59:60 June 30, 2015. This addition, however, could shake up the Internet and the stock market.

Similar in concept of a leap day, a leap second is added to the UTC timezone in order to realign earthbound atomic clocks with astronomical time. Since the Earth is slightly tilted on its axis, its rotation causes our clocks to imperceptibly slow down. Eventually, the discrepancy between Earth’s time and astronomical time is wide enough for the entire planet to lose a whole second.

Time and Date, online experts on temporal news, explains that leap seconds have been periodically added for 43 years.

“Did you notice? The last leap second was added at 23:59:60 UTC on June 30, 2012,” the website says. “Since 1972, a total of 25 seconds have been added. This means that the Earth has slowed down 25 seconds compared to atomic time since then.”

So what does this cosmic, temporal adjustment mean for the millions of insignificant human beings on Earth?

A lot, actually. High-profile companies that rely on the Internet are bracing themselves for a bite-sized Y2K. During the last leap second in 2012, Yelp, Linkedin, Reddit and Qantas Airways experienced numerous issues because their computers recorded the same second twice. The stock market, an environment characterized by split-second decisions and rapid change, almost always experiences a “flash crash” when the clock strikes midnight on leap second day.

The United States may even abolish the leap second on the recommendation of the US Naval Observatory due to the risks it poses to public and private business.

Fortunately, many companies have already planned around the time disruption. Google’s software has automatically updated to compensate for the extra second since 2011. Amazon Web Services stated that it was simply going to ignore the leap second altogether for “a short period of time” until it figured out how to deal.

The main takeaway from the leap second is this: Come July 1st, you better set your watch one second behind.

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