Mechanical waves, such as sound waves, cannot travel faster than the speed of light in vacuum or air. According to the fundamental principles of physics, information and energy cannot be transmitted faster than the speed of light in a vacuum, which is approximately 299,792,458 meters per second (or about 186,282 miles per second).
There have been instances where certain phenomena or particles appear to travel faster than the speed of light in a medium, such as water or other materials. However, it is important to note that these cases involve the propagation of disturbances rather than the actual transfer of information or energy.
One example often mentioned is the Cherenkov radiation, which occurs when a charged particle moves through a medium at a speed greater than the phase velocity of light in that medium. This creates a visible shockwave of electromagnetic radiation. It may give the impression of light traveling faster than the speed of light in that medium, but in reality, it is the particle's motion that produces the effect, not the transmission of information.
As for light, it always travels at the speed of light in vacuum, regardless of the medium it passes through. In different materials, such as glass or water, light travels slower than its speed in vacuum due to interactions with atoms or molecules in the medium. This is known as the refractive index, but it does not violate the speed limit imposed by the vacuum speed of light.
The speed of light in vacuum is considered a fundamental constant of nature, and it plays a crucial role in the theory of relativity and our understanding of the universe. Experimental observations and measurements consistently support the notion that no information or energy can be transmitted faster than the speed of light in vacuum, making it an essential principle in modern physics.