Why so many spacecraft carry magnetometers

Let’s dissect the anatomy of Adidas Smart Balls being used at The FIFA Club World Cup. The balls have sensors within them that help to determine the speed and direction using accelerometers. Now, these balls are also useful in the determination of goals via the goal line technology, as they have magnetometers that sense the position of the ball on the field. How the signals are shared The balls, like any other smart ones, have copper wires that conveys communication using an antenna array mounte