Just because people are corporeal born to this world doesn't mean that they understand everything about it, similarly just because somebody's died doesn't mean that they understand everything about the incorporeal world
We experience and understand the world through signals that are received by the senses and interpreted by the brain - and both stages are subject to distortion
In recent years, with a method called VLBI that uses quasar observations, and by GPS we have begun to understand the absolute movement of tectonic plates