The speed of sound is the distance travelled per unit of time by a sound wave as it propagates through an elastic medium. At 20 °C (68 °F), the speed of sound in air is about 343 metres per second ...

The terahertz quantum cascade laser on its mounting. Credit: University of Leeds Lasers that switch on and off billions of times per second are the backbone of optical communications networks, but ...

Settling a half century of debate, researchers have discovered that tiny linear defects can propagate through a material faster than sound waves do. These linear defects, or dislocations, are what ...

A research team at City University of Hong Kong (CityU) has discovered a new type of sound wave: the airborne sound wave vibrates transversely and carries both rotation and orbital angular momentum ...

Researchers at ETH Zurich have managed to make sound waves travel only in one direction. In the future, this method could also be used in technical applications with electromagnetic waves. Water, ...

It’s a question I’m sure was keeping you up at night: can you make an object spin with a sound wave? The answer, generally speaking, used to be no. Now, though, mechanical engineers have taken a look ...

On Mars, the speed of sound depends on its pitch. All sound travels slower through Mars’ air compared with Earth’s. But the higher-pitched clacks of a laser zapping rocks travels slightly faster in ...

How far can sound travel through space, since it’s so empty? Is there an echo in space? – Jasmine, age 14, Everson, Washington In space, no one can hear you scream. You may have heard this saying.

Acoustic waves in gases, liquids, and solids usually travel at an almost constant speed of sound. Rotons are an exception: their speed of sound changes significantly with the wavelength, it is also ...

In the ETH experiment, self-oscillations (blue-red) cause sound waves (green, orange, violet) to travel through the circulator only in one direction. Credit: Xin Zou Researchers at ETH Zurich have ...