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 ...

Sound plays an important role for many animals, helping them navigate and hunt. Echolocation is the ability of animals like bats and dolphins to locate objects by emitting sound waves and interpreting ...

Can't see the video? Download an mp4 [10.4 MB] version of this video. Smart phones are expensive so please take care not to swing yours too close to a wall or a person or inside a sock that's almost ...

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 ...

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 ...