## Why ratios of the scale factor?

I introduced the notion of a scale factor as a concept separate from a fixed and comoving cosmological lattice in a previous post. Developing that idea lead to the Hubble non-constant, . Later, in developing a couple of simple forms of the Friedmann equations, we encountered something of the form . This raises a question. Why all these ratios of a(t)? The answer is simple. The scale factor depends on the scale of the comoving cosmological grid that’s being used. Since proper distances depend upon the product of the scale factor and the size of the grid, , changing the size of the...

Read More## The Hubble non-constant

In a previous post, I introduced the notion of a 3-dimensional cosmological lattice. The idea is that, very roughly, the grid spacing is about the mean spacing between galaxies now. We break the order on the grid into two components, an ordinal part against which the position of the galaxies is fixed, or nearly fixed; and a scale part, which is a function of time, . One cell of this grid looks like this: The distance between any two galaxies, say and , will be assuming a Euclidean space. Since it transpires that experimental evidence indicates that the assumption that our visible universe...

Read More