Physicians only confirmed the upper limit for the speed of sound in the universe

Einstein’s theory of special relativity gave us the speed limit of the universe – light in a vacuum. But the absolute top speed of sound, by any means, is somewhat difficult to constrain.

It is impossible to measure the speed of sound in every single material in existence, but scientists have now managed to reduce the upper limit based on fundamental constants, universal parameters, by which we understand the physics of the universe.

According to the new calculation, the speed limit is 36 kilometers per second (22 miles per second). This is almost twice the speed of sound traveling through the diamond.

Both sound and light travel as waves, but they behave slightly differently. Visible light is a form of electromagnetic radiation, so named because light waves include electric and magnetic fields. These fields produce a self-destructive electromagnetic wave that can travel in a vacuum – and has a top speed of about 300,000 kilometers per second. Slows traveling through a medium such as water or atmosphere.

Sound is a mechanical wave caused by vibration in a medium. As the wave travels through the medium, the molecules of that medium collide, transmitting energy.

Therefore, the harder the medium – the harder the compress – the faster the sound travels. For example, water has more tightly filled particles than air, and that is why partially whales can transmit such vast distances across the ocean.

In a solid solid, like a diamond, sound can also travel faster. We take advantage of this property to study the inside of the Earth when sound waves from an earthquake travel through it. Even we can use it to understand the interiors of wires.

“Soundwaves in solids are already extremely important in many scientific fields,” said Chris Picard, a scientist at the University of Cambridge in the UK.

For example, seismologists use sound waves introduced from the depths of an earthquake into the Earth’s interior to understand the nature of seismic events and the properties of the Earth structure. They are of interest to scientists because sound waves are related with significant elastic properties. Ability to resist stress. ”

So far, you can see the problem with interrupting the speed of sound. How do we account for all possible materials in the universe to set an absolute upper limit on the speed of sound?

This is where fundamental constants are useful. To calculate the speed limit of sound, a team of scientists from Queen Mary University in London, University of Cambridge in the UK and Institute of High Pressure Physics in Russia found that the range of motion depends on two fundamental constants.

These fine structures are stable, characterized by the strength of electromagnetic interactions between elementary charged particles; And the proton-to-electron mass ratio, which is the rest mass of the proton divided by the rest mass of the electron.

“Fine-structure constant and finely tuned values ​​of the proton-to-electron mass ratio and the equilibrium between them regulate nuclear reactions such as proton decay and nuclear synthesis in stars, leading to the creation of essential biochemical elements,” Including carbon. This equilibrium provides a narrow ‘habitable zone’ in space where stars and planets can form and life-supporting molecular structures can emerge, “the researchers write in their paper.

“We show that a simple combination of fine structure constant and proton-to-electron mass ratios results in a more dimensionless quantity with an unexpected and specific implication for a major property of condensed phases – the speed at which waves Solids travel. Liquids, or the speed of sound. ”

To confirm their equation, the team experimentally measured the speed of sound in a large number of elemental solids and liquids, and returned results consistent with their predictions.

A specific prediction of team theory is that the speed of sound must decrease with the mass of the atom. According to this prediction, sound must move fastest through solid atomic hydrogen – which can only exist at high pressures, above 1 million times (the Earth’s atmospheric pressure at sea level).

Experimentally it would be extremely difficult to obtain a sample to verify this prediction, so the team relies on calculations based on the properties of solid atomic hydrogen between 250 and 1,000 gigafasels. And he found that, again, the results agreed with his predictions.

If the results of applying the team’s equation remain consistent, it can prove to be a valuable tool, not only for understanding individual materials, but for the wider universe.

“We believe the findings of this study,” said physicist Kostya Trachenko of Queen Mary University of London, “by helping us discover and understand the limits of various properties such as viscosity and thermal conductivity relevant to high-temperature superconductivity.” There may be further scientific applications. ” , Also quark-gluan plasma and black hole physics. ”

The research has been published in Science advance.


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