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 ...

Twist and shift: Incident beams with opposite orbital angular momentum (green spiral) reflect from a spinning surface: some of the light in the reflected beam has been red-shifted after reflection and ...

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 ...

Radar is quite spectacular in telling us exactly where rain is falling by pinging precipitation with radio waves! Our weather radar can determine more than just a storm’s location, but its movement as ...

At the time of its construction in the 1950s, the Dwingeloo Radio Observatory was the largest rotatable telescope in the world with a dish diameter of 25 meters. It was quickly overtaken in the ...

Almost all measurements of motion in astronomy make use of a law of physics called the Doppler effect. This change in the wavelength (or frequency, color, or pitch) of a wave emitted by a moving ...

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 ...