4D Balloon Theory is an extension of Einstein's Theory of Relativity. This theory does not challenge Einstein's mathematical model but instead challenges Einstein's description of physical reality based on a flaw in the translation of the Theory of Relativity from mathematical model to descriptive model. That flaw is the term "dimension."
The 4D Balloon Theory (4DBT) has to describe everything that Einstein's Theory of Relativity has touched because Relativity's flaw ruins just about every description of physical reality it tries to explain. Thus, 4DBT must be a large theory covering a wide spread of topics due to the subject matter involved.
The 4D Balloon Theory Outline breaks the process of presenting the descriptive model of physical reality into four sections:
1. The description of the expansion of the universe.
The process of expansion is, without a doubt, the strangest and most otherworldly phenomenon in the universe and the accurate description of this phenomenon is neglected due to its difficulty. That difficulty is due, in part, to the flaw in Relativity. The other part of the reason the strangeness of expansion is neglected is the actual difficulty of the subject matter.
2. The Definition of Dimension
The term dimension, under Relativity, is problematic. The mathematical definition of the term is well understood. However, that definition cannot be used to describe physical reality and a physical definition of the term "dimension" has not been created and cannot be created under the present conditions within the standard model. In this section of the outline these problems are resolved creating new problems.
3. The Four Dimensional (4D) Description of Our Universe
Our universe must exist as the three dimensional surface of a four dimensional object which exists in a four dimensional space outside our universe. The true nature of our universe can only be studied as a surface. This section of the theory (as described in this outline) does exactly that.
4. Description of the Effects of Four Dimensional Reality on the Universe
The expansion of the universe is caused by a force of four dimensional origin (outside our universe) working upon our universe. This fact has many interesting implications and valuable explanatory power.
According to the Big Bang Theory, the Universe is expanding. However, if you think that "The Big Bang" is a good name for the phenomenon that is happening to the Universe, then you do not understand the Expansion of the Universe because the name evokes the impression of an explosion of motion on the part of matter, the stuff of the universe. In reality, not a single atom of matter in the entire universe has moved so much as a nano-meter due to the power of the Big Bang in the entire existence of the Universe. Every single single particle that ever existed presently occupies the same location in the universe that it did at the moment of the "Big Bang" and it will forever occupy that location because:
The Big Bang Theory describes a universe at rest, devoid of meaningful motion.
How can this be? How can the Universe be expanding without anything moving?
I did say that the expansion of the universe is the strangest phenomenon in the Universe.
The "HOW" cannot be answered yet because the conceptual framework has not been built yet. That will happen in later sections and is the door through which you will be introduced to the Fourth Dimension as the shortcomings of Relativity and the Standard Model are revealed.
In this section, the expansion of the Universe will be described in accordance with both the Standard Model and 4DBT. The Standard Model's description of expansion is fairly accurate, though its explanation of the cause of expansion is laughably wrong.
The volume of every cube is increasing but nothing is moving into or out of the cubes. Everything is exactly where it has always been based on the coordinate system of the cube. It is difficult to imagine the volume of the entire universe increasing, but it is easy to imagine the volume of a cube increasing. If you add the concept of an expanding cube to the concept of a universe filled with these cubes, you get the expansion of the universe.
Once, each BCMC was very small and the matter in each cube occupied 100% of the smace within each cube. That means that at one point the Local Cube had no empty space at all and was completely full of matter. Nothing could move because there was no space to move in. The situation in the universe was just stuff everywhere. The Big Bang is simply the process of space coming into existence within the cube. Nothing ever moved due to anything except the four known forces (Strong, Weak, Electro-Magnetic, and Gravity).
The Balloon analogy is perfect. Educators often use the analogy but add the caveat that is is not perfect. I say is is perfect and that the scientific community cannot prove me wrong because they cannot talk about the analogy with any detail for lack of vocabulary.