Black Holes, Satellite Navigation, and a Crowded Radio Highway

Global satellite navigation systems rely on precise measurements of Earth's position, which in turn depends on observations of black holes at the centers of distant galaxies. Scientists use radio telescopes to receive radio waves from black holes, but in recent years, electromagnetic pollution from WiFi, mobile phones, and satellite internet has become increasingly severe, crowding the radio spectrum and interfering with observations of black hole signals. This threatens satellite navigation and many other services that rely on precise Earth positioning. Solving this problem requires international cooperation, securing more radio spectrum resources for geodesy at World Radio Conferences, or establishing radio quiet zones around essential radio telescopes.