Question

(1) Radio waves and light are electromagnetic waves and transverse waves that can operate in a medium or in space.

What is an Aether or ether?

Upon which medium does sound travel the fastest?

(2) Some scientists think that ether does exist but does exist in another dimension that we cannot see. Can you elaborate on this?

Answer 1

(1).In Johann Bernoulli theory, all space is permeated by aether containing "excessively small whirlpools." These whirlpools allow for aether to have a certain elasticity, transmitting vibrations from the corpuscular packets of light as they travel through.
This theory of luminiferous aether would influence the wave theory of light proposed by Christiaan Huygens, in which light traveled in the form of longitudinal waves via an "omnipresent, perfectly elastic medium having zero density, called aether". At the time, it was thought that in order for light to travel through a vacuum, there must have been a medium filling the void through which it could propagate, as sound through air or ripples in a pool. Later, when it was proved that the nature of light wave is transverse instead of longitudinal,

b.Sound travels fastest through solids. This is because molecules in a solid medium are much closer together than those in a liquid or gas, allowing sound waves to travel more quickly through it. In fact, sound waves travel over 17 times faster through steel than through air. The exact speed of sound in steel is 5,960 meters per second (13,332 mph)! But, this is only for the majority of solids. The speed of sound in all solids are not faster than in all liquids.

(2)Universe is a multi dimensions sphere of dark matter
To imagine that we may imagine a cube of dark matter
Three dimensions cube id composed of six two dimensions squares. In case of the four dimensions cube instead the squares we put three dimensions cubes. And so, four dimensional cubic is composed of six of four dimensions cubes, in a way which we can