Why do transverse waves travel faster than longitudinal waves?
In solids, p-wave (longitudinal) speed is compressive strength [Oops! I mean modulus] divided by density of the medium; s-wave (transverse) speed is sheer strength [Oops! I mean modulus] divided by density. Transverse waves are always slower than longitudinal waves in the same medium because sheer strength is always less than compressive strength. Earthquake waves, for example: The p-waves are many times faster than the s-waves. [Modulus us like a spring constant; it’s the ratio of stress to strain.] A gas has no sheer strength, so it does not provide a medium for transverse waves. So there are no transverse waves in air that can be compared to sound waves. As for light waves, the popular myth is that there is no ether—no light wave medium. In fact, it is true that the maths of general relativity work okay without saying anything about a medium; but that doesn’t mean there is no medium; and mathematical space-time is not a medium. James Clerk Maxwell said that if there is an ether, i
