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 ...

The speed of light in a vacuum is the same wherever you measure it in the universe, according to Einstein's special theory of relativity. Whether you're sat on Earth, Mars, or Zoozve, if you measure ...

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 ...