How do you detect something moving faster than light? I’m not sceptical, just curious.
IIRC, the feat is accomplished by measuring the interval from emission to detection and comparing that ‘time interval’ to how fast the two events would occur at light speed in a vacuum. It’s kind of like mathematically showing the Sun has a greater radius than the surface area would indicate if using the Euclidian equation for finding the surface area given the radius, or finding the radius of a spherical object given the surface area. Richard Feynman gave an amusing lecture on this topic in his Caltech lectures.