Sound consists of periodical compression pulses printed into the air from a source. These pulses propagate outwards with equal speed in every direction. The distances between consecutive pulses is known as the 'wavelength'. The number of pulses passing through a point in space per second is called the 'frequency' or 'pitch' of the sound.
This is the case when the source is at rest relative to the air. However, if the source is moving, the wavelength is shortened in the front and lengthened in the back. The observer at rest receives a higher pitch of sound from an approaching source and a lower pitch of sound from a receding source. A familiar example is the varying pitch of the whistle as a train passes by. Experimenters found that light-waves also produce Doppler effects (see ill.). An approaching light-source produces a 'blue shift', a receding one produces a 'red shift' . From the spectral Doppler-shift of a star, astronomers can calculate its approaching or receding velocity. -- In the 1920's astronomers discovered that the majority of the 'naked-eye stars' were in fact 'galaxies', each consisting of billions of stars. Surprisingly, in every direction their light showed great redshifts. These cosmic redshifts were taken to be equivalent with the receding velocities of the galaxies and found to be proportional to their distances from the Earth. The 'velocity-distance relation' became known as Hubble's Law of the Cosmological Red-shift.
At first it seemed that the Earth had once again become the center of the Cosmos. - However, theorists showed that dots painted on the skin of a balloon will recede from each other, similar to the galaxies, when the balloon is inflated. Another theory presented a three dimensional analogy using a 'raisin-cake'. As it expands in the oven, each raisin sees all other raisins receding at speeds proportional to their distances.
This analogy gave a plausible mechanical model of the Expanding Universe. It followed that at one instance of the past all galaxies were close together and began their expansion from a mutual point in space. Thus, the Universe must have exploded from a Primeval Atom with a BIG BANG !
Of course, all theories of the expanding universe are based on the assumption that Hubble's Cosmological Redshift is really caused by the Doppler Effect of light-waves. There were other possible solutions, for example, the 'Gravitational Red-shift' or the different 'Tired-Light' theories. Nevertheless, modern mathematical cosmology eventually concluded that Einstein's General Relativity, with its non-Euclidean Space-curvatures together with the mysterious Big Bang of the Primeval Atom, was considerably more attractive.
Aethro-Kinematics presents an alternate solution of a non-expanding, non-exploding, non-Big-Banging cosmos; a simple Rotating Universe. The theory also clarifies the real kinematics of the Doppler-shift of light-waves in Aether and explains how the whole phenomenon of 'cosmic red-shift' is produced in the prisms of Earthly laboratories.