Technology makes everything possible. We have seen robot that can play violin, cell phone that powered by water, and now we have the high tech football that can tell the referees when it has crossed the line. Here's how the high tech football works:
"Wires embedded in the pitch around the goalmouth emit a magnetic field which can detect the presence of a specially-designed ball fitted with a sensor. The football can then be tracked its exact position around the pitch.Pretty cool, huh? No more wrong judgement by the referee. The high tech football, however, still need to be tested more thoroughly, and proven that it's 100% accurate before the International Football Association Board approves it to be used in professional tournaments, including the World Cup.
An encrypted signal is then sent to a watch worn by the referee to let them know whether the ball has crossed the line."