Physicists Calculate Upper Limit For Speed Of Sound In The Universe

Sound waves can travel to up to 36 kilometers or more than 22 miles per second when traveling through solids or liquids, a new study by a team of physicists revealed. The physicists said that their calculation could be the first known variables representing the threshold of sound waves.

Before this new finding, the speed of sound was measured based on Albert Einstein’s theory of special relativity that identified sound waves threshold similar to that of the speed of light (300,000 kilometers or over 186,000 miles per second).

In a study, published in the journal Science Advances, the physicists said to calculate for the threshold of the speed of sound, they factored in the two dimensionless fundamental constants. These constants are the fine structure constant and the proton-to-electron mass ratio.

The physicists explained that these two fundamental constants have already been used in calculations needed to understand the Universe. For instance, the dimensionless fundamental constants are also the basis for calculations of nuclear reactions, proton decay, and nucleosynthesis in stars. The balance between the fundamental constants could also point to the habitable zone where possible life forms could start outside Earth.

With identifying the upper limit of sound, their finding also became significant in other fields of studies. Setting a known upper threshold of sound is particularly crucial to studies that test the limits of matter such as materials science and condensed matter physics.

“We believe the findings of this study could have further scientific applications by helping us to find and understand limits of different properties such as viscosity and thermal conductivity relevant for high-temperature superconductivity, quark-gluon plasma and even black hole physics,” Kostya Trachenko, professor at the Queen Mary University of London, said in a press release.

Another major finding of the study is the possibility that sound travels the fastest in solid atomic hydrogen. To come up with this result, the physicists tested sound as it travels through different materials.

By performing sophisticated quantum mechanical calculations, the team of physicists found that sound can almost reach its upper limit when traveling in solid atomic hydrogen. The speed of sound came nearly twice as fast as the speed of sound in diamond given that diamond is already the hardest known material in the world.