Whether electromagnetic or gravitational, the speed limit of any wave in a vacuum environment has remained the same since Albert Einstein successfully developed the special theory of relativity in 1905. However,
To get this result, physics professor Kostya Trachennko and his colleagues used two famous constants in physics: the ratio between the mass of the proton and the mass of the electron, in addition to the crystal structure constant.
Trachenko commented that science has a pretty solid foundation to be confident in the accuracy of the constants just mentioned, because if they moved just a little, the Universe would be much different from what it is today.
Sound is a wave transmitted in matter by interacting particles. The speed of sound depends on the mass density (specific gravity) of the matter – that is, the atoms that make up the matter are close together,
Trachenko and his colleagues took advantage of this fact, along with the proton-electron mass ratio and the fine structure constant, to calculate the maximum speed of sound when traveling through liquids or solids: in theory, sound
`We still know that diamonds will produce the highest speed of sound transmission, because they are the hardest material, but we don’t know if there is a theoretical speed limit,` Professor Trachenko
The speed of sound also depends on the mass of the atoms present in the matter, so researchers predict that solid metallic hydrogen – a material that exists theoretically, could be present in the cores of planets.
However, professor Graeme Ackland working at the University of Edinburgh said that the calculations of Trachenko and his colleagues did not calculate the maximum speed of sound.
Professor Ackland believes more testing is needed to observe the speed at which sound travels in heavier elements.
Refer to New Scientist