On June 30, time will stand still.
Just for a second -- a leap second.
Since 1967, when clocks went atomic, human timekeeping has been independent of the earth’s rotation. The problem is, the planet is slowing down and clocks are not. So every few years, to get everything back in sync, scientists add a second. They’ve done it 25 times since 1972. A leap second was last added to the clock in 2012, during a weekend, which wreaked havoc online. It caused Reddit, Foursquare, Yelp, LinkedIn, Gawker and StumbleUpon to be knocked offline entirely, as well as hundreds of flights to be delayed in Australia.