635563203529410139-XXX-GAN-SHOP-CLOCKS-022713-2The year 2015 will have an extra second — which could wreak havoc on the infrastructure powering the Internet. At 11:59 p.m. on June 30, clocks will count up all the way to 60 seconds. That will allow the Earth’s spin to catch up with atomic time. The Earth’s spin is gradually slowing down, by about two thousandths of a second per day, but atomic clocks are constant. That means that occasionally years have to be lengthened slightly, to allow the slowing Earth to catch up with the constant clock. But last time it happened, in 2012, it took down much of the Internet. Reddit, Foursquare, Yelp and LinkedIn all reported problems, and so did the Linux operating system and programs using Java. The reset has happened 25 times since they were introduced in 1972, but the computer problems are getting more serious as increasing numbers of computers sync up with atomic clocks. Those computers and servers are then shown the same second twice in a row — throwing them into a panic. More