Have you ever wondered what is the Upper Limit for Speed of Sound in The Universe? I guess at one point or the other we might have looked for this answer. And in a new discovery Physicists have found this out. It’s so fascinating no? The universe I mean. Since the time Einstein disclosed his relativity theory, the universal speed of an electromagnetic wave or gravitational wave moving through a vacuum has been known. The universal speed of any kind of wave is not a secret since 1905, but for the first time, the maximum limit at which sound can travel has been discovered. Yes, folks, this is the first time speed of sound traveling through solid or liquid has been discovered.
Well, what is the Upper limit for Speed of Sound in the Universe? It is 38 km/sec. That’s not so fast, in fact, its 8000 times lower than the speed at which light travels through a vacuum. What a discovery! This discovery was made by Kostya Trachenko and his colleagues from Queen Mary University. To facilitate this process, they began by taking two very known physical constants: the fine structure constant and the ratio of Proton Mass to Electron mass.
Insights about the Discovery
The reason they took these constants are that every physicist knows these values for sure. These are two constants that cannot change even slightly. And if they do change, the universe will never look be the same. You might not have a carbon life! Since Sound waves transmit when neighboring elements interact, that means that its speed depends on the density of a material. And also how the atoms are bound, like how tightly or loosely atoms are bound in a material. There is a limit to how fast the atoms are move, so sound can travel only so quickly. So this helped them in calculating the Upper Limit for Speed of Sound.
Trachenko and his colleagues were aided by the Proton and electron ratio in calculating the speed at which sound can move through liquid or solid. Theoretically speaking. And that Upper Limit for Speed of Sound is about 38 km/sec. And these Physicists had experimented with 133 materials and the limit was never broken. But Graeme Ackland from the University of Edinburgh doesn’t think this procedure gives accurate results “You can use these fundamental constants to get something with units of velocity, but I can’t quite see a good fundamental reason for why it abounds.” He says this doesn’t convince him. So this means that there is a window for more research and this upper limit is subject to change.