What is the ultimate speed of sound transmission?

To test their equation, the team experimentally measured the speed of sound travelling through a variety of elements, solid and liquid, and returned results which was consistent with the predictions.

Another specific prediction of the theory is that the speed of sound should decrease as the atomic mass of the element in the medium increases.  Thus, the ultimate speed of sound should be the speed at which waves pass through a solid hydrogen crystal.  The problem is, the solid hydrogen can only exist at extremely high pressure -- 100 gigapascals,1 gigapascals is 1 gpa,1000000MPa, that is 1 million Pa.

So it would be very difficult to verify it through direct experiment. Therefore, the team calculated it based on the properties of solid hydrogen. They found that the results were again match the theoretical expectations.

If the results of the equation keep consistent, it may prove to be a valuable tool for understanding not only specific materials, but also the entire universe.

Kostya Trachenko, a physicist at Queen Mary University of London, said: “We believe this research can help us discover and understand the limits of different properties associated with high-temperature superconductivity, such as viscosity and thermal conductivity; It also has potential for further applications in quark-gluon plasma and even black hole physics.

The study was published in the journal‘Science Advances’.