A group of researchers from Queen Mary University London, University of Cambridge, and the Institute for High-Pressure Physics in Troitsk have revealed their findings on the highest possible limit at which sound can travel – 36 kilometers (22 miles) per second. That is twice as fast as the rate at which sound travels through diamond which is the hardest substance on earth.
Waves are disturbances that can send energy from one position to the other. Sound waves move through different materials and substances such as water and air. The speed at which sound waves travel depends on the medium through which they are moving. Sound waves move faster through solid materials than they would through gases or liquid substances. If you have been on rail lines, you would probably have noticed that you can hear the sound of an approaching train through the tracks which are solid faster than through the air.
Albert Einstein’s theory of special relativity states that the fastest speed at which electromagnetic waves travel is the speed of light, which is about 300,000 kilometers (186,282 miles) per second. It was however unknown, until now, if the speed at which sound waves travel has a maximum limit. The researchers were able to prove that the maximum limit of sound waves is dependent on two constants – the ratio of proton-to-electron mass, and the fine structure constant, Daily Mail reports.
These two constants are crucial in our understanding of the galaxy. Their values decide certain nuclear reactions such as Stellar Nucleosynthesis (nuclear synthesis in stars). The balance in the values of the constants creates a narrow zone suitable for the formation of planets and stars. The research which has been published in the Science Advances journal shows that the two constants play an even greater role. These numbers can be used to set a limit to certain material properties such as a limit on the movement of sound waves.
After testing their theory on different substances and mediums, the researchers predicted that the movement of sound waves should decline with the mass of an atom. This means that sound waves will move very fast through solid atomic hydrogen. This poses a small problem since solid atomic hydrogen can only be obtained at very high pressure – above 1 million atmospheres only, which can be found in big gas planets such as Jupiter.
At that kind of pressure, hydrogen becomes a solid metallic conductor of electricity at room temperature. To test their predictions, the researchers executed a highly advanced quantum mechanical calculations and discovered that the speed at which sound waves travel through solid atomic hydrogen is close to the speed of light.
“The study of the movement of sounds is very important. Seismologists use sound waves caused by earthquakes to further their comprehension of seismic events and to also understand the composition of the Earth,” Professor Chris Pickard, a professor of Materials Science at the University of Cambridge explained. “Material scientists also use sound waves in relation to crucial elastic properties such as the ability to tolerate stress.”