A typical description of the “expanding universe” of modern astronomy reads as follows:
The common analogy likens the galaxies to spots on the surface of a balloon that is being inflated. As the rubber stretches, all the spots move away from each other.
But this description is immediately followed with an explanation of the origin of the motion, the so-called “Big Bang”, that is totally incompatible with the motion as described. According to the Big Bang hypothesis, the galaxies are moving outward from a common point of origin, and the apparent recession in all directions when viewed from a particular location is due to velocity differentials. But the spots on the surface of an expanding balloon are, in actual fact, moving outward from each other, not from a common point. Thus, if the motions of the galaxies originated from a Big Bang they are not similar to the motions of spots on an expanding balloon, whereas if the galactic motions do have this character they could not have originated from a Big Bang. At the moment there may not be any available means of deciding between these alternatives, but the fact that the analogy is so widely used without recognition of the inconsistency that is involved shows that there is a definite need for a better understanding of the nature of the type of motion that takes place when a balloon expands.