MADISON -- What if the speed of light is a constant only most of the time? What if gravity sometimes pushed instead of pulled? Scientists are increasingly asking what would seem like far-out questions ...

The Doppler shift of sound or light waves from a moving source is familiar to physicists and non-physicists alike. Now, researchers in China and Australia have seen the more exotic inverse Doppler ...

The inverse Doppler effect has been observed in an experiment for the first time. Nigel Seddon and Trevor Bearpark at BAE Systems in Bristol in the UK saw the effect in an electrical transmission line ...

Everyone has experienced the Doppler effect: an ambulance's siren has a higher pitch as it approaches you, and a lower pitch when moving away. Now imagine that the pitch goes down as the ambulance ...

The pitch of a blaring car horn rises as the vehicle approaches and falls as it moves away. That’s the Doppler effect, and it also occurs for electromagnetic radiation, enabling police to catch ...