Once again we are going to adjust the world’s clocks by one second. This time it will happen on June 30, when we insert another leap second in Coordinated Universal Time (UTC), the standard international time scale. In theory, all UTC clocks should insert a second labeled 23h 59m 60s (the leap second) following one labeled 23h 59m 59s UTC. This is equivalent to having all of the clocks in the world stop for one second at that time. Are you ready for it?