June 30 is 'Leap second' day

June 30 this year will officially be a bit longer than usual because an extra second, or 'leap' second, will be added to the day, according to NASA. "Earth's rotation is gradually slowing down a bit, so leap seconds are a way to account for that," said Daniel MacMillan of NASA's Goddard Space Flight Centre in Greenbelt. Strictly speaking, a day lasts 86,400 seconds. That is the case, according to the time standard that people use in their daily lives-Coordinated Universal Time, or UTC.