At tonight's opening match between Brazil and Croatia, the referees will be wearing smartwatches that read "GOAL" and vibrate when a team scores. It's part of a new "unhackable" goal line detection system, the first to ever be used in the World Cup.
According to FIFA, this closed-loop system includes seven incredibly high-speed cameras, that snap 500 shots per second, positioned around both goals, at each of Brazil's 12 World Cup stadiums. These cameras can measure the position of the ball every two milliseconds according to the GoalControl, the German company that makes it. "When the ball passes the goal line, all referees receive in less than one second a vibration and optical signal at their watches," the company explains.
FIFA has historically resisted goal-line detection systems, which use cameras and sensors to determine when a goal is good or not. But it's reconsidered its stance in the years since the last World Cup, where a referee wrongly disallowed a goal made by England's Frank Lampard in a game against Germany, which England ended up losing. The uproar over the bad call apparently made FIFA reconsider—and it's been testing GoalControl's 4D detection system in the years since.
Of course, the final call will still lay with the ref, regardless of what their smartwatch says. It's easy to imagine how career refs could even feel resentful of being replaced by what amounts to a very sophisticated CCTV system. I wonder if that, in and of itself, could affect the way calls are made this year. We'll get a chance to see tonight! [GoalControl; PhysOrg]