The theory of expanding earth is something, that I have supported earlier, too. In fact I was influenced by Neill Adams videos. But let me explain, why I've looked at them.
It goes like this:
If we start from relativity and try to connect it to quantum-mechanics, we first have to make spacetime three-dimensional, because our observed world is three-dimensional. String-theory can't possibly be true, because we don't experience ten (or more) dimensions. This is so, because the term 'dimension' refers to various things, but one could say dimensions are the possible number of degrees of freedom. Since with any dimension we add a lot of degrees of freedom, ten dimensions are not possible. (to any degree of freedom there has to be an observed phenomenon in nature)
Imagine symmetry. Our observed world is symmetric. Makes no much difference, if we move back or forth, but it makes a difference, if we move up or down. Spacetime is antisymmetrric and space isn't. How put that together?
Imagine everything to turn left in spacelike direction. Where that is, depends on where you point to. This generates a three dimensional pattern and we're a part of that. We would certainly experience the world from our own state of being. This should be a world, wherever we go and how fast. This is the essence of relativity. There is no such thing as absolute space and where ever we go, your observation will be based on our own state of being. (Space is a relative observation, relative to ourselfs).
That is in fact counter-intuitive, but it is a proven (!) fact.
Now antisymmetry makes everything of opposite sign, if you change the direction. In spacetime-diagrams we could say; left is negative and right is positive (or any other duality names). As a matter of fact our world is not two dimensional but three dimensional and we must extend duality to triality. With such a model it is possible to model particles, just out of 'directions' of antisymmetry. It is pretty counter-intuitive, this is why I can just ask you to try that yourself. This leads to a vortex model, if we switch from spacetime view to real space.
After being there, it is easy to think the earth could expand, because the model doesn't require particles to move inside the earth. If the 'particle concept' doesn't hold, we would have to think in different terms. The particle concept is a corner stone of modern science and to abandon it, is next to impossible. But - that is my personal point of view - we have to.

TH