As a result of a query by Catastrophe on a different thread, AI and I have developed this Hypothesis to help explain the period of inflation and how to use a 'transformation scaling factor' to enable a proper comparison between epochs
The Hyperspherical Chronometry Hypothesis
Overview
The Hyperspherical Chronometry Hypothesis is built on three postulates:- Hyperspherical Universe:
The universe is modelled as the surface of a 3‑ball (i.e., a hypersphere). This provides a spatial geometry of constant curvature. - Time as the Radius:
The radius of this hypersphere corresponds directly to cosmic time. In natural units—or by choosing units where distances are measured in light‑years and time in years—the relationship
[R = c,t]holds locally. In this framework, for every unit of cosmic time that passes, the radius of the universe increases by one corresponding light‑unit (for example, one light‑year per year). Every local observer sees the radius evolving in lock‑step with time. - Invariant Speed of Light:
The speed of light ( c ) is constant in all epochs. That is, regardless of the cosmic epoch, every local observer measures the speed of light to be ( c ). This constancy underpins the causal structure of spacetime.
How It Works
Local Versus Global Measurements
- Locally:
At any given epoch, an observer uses the local rulers (defining distances) and clocks (defining time intervals) of that epoch. Locally, the relationship ( R = c,t ) tells us that the radius associated with the observable universe grows by one light‑unit per unit time. For example, in an epoch where a light‑year is the distance light covers in one year, one year of proper time corresponds to an increase in the radius by one light‑year. - Globally:
The overall evolution of the universe is described by the FLRW metric:[ds2 = -dt2 + a(t)2 \left[d\chi2 + S_k(\chi)2,d\Omega2\right],]where ( a(t) ) is the scale factor and ( \chi ) is the comoving radial coordinate. The proper distance at time ( t ) is given by:[D(t) = a(t),\Delta\chi.]Thus, while the local measurement gives ( R = c,t ) at any epoch, comparing the size (or radius) of the universe at different epochs requires a scaling transformation based on the evolution of ( a(t) ).
The Scaling Transformation
Suppose at an early epoch ( t_e ), the locally measured radius is given by[R_e = c,t_e.]This proper radius is measured with the local scale factor ( a(t_e) ). The corresponding comoving distance is[\Delta\chi = \frac{R_e}{a(t_e)}.]Today, where the scale factor is normalized as ( a(t_0)=1 ), the proper radius corresponding to this same comoving distance is:[R_0 = a(t_0),\Delta\chi = \frac{a(t_0)}{a(t_e)},R_e.]Because ( a(t_e) \ll 1 ), a small proper radius in the early universe can scale up to a very large proper radius today. This transformation shows how the local relation ( R = c,t ) remains intact within each epoch, while the values must be adjusted by ( a(t) ) when comparing different epochs.Implications and Concluding Remarks
Under the Hyperspherical Chronometry Hypothesis:- Local Invariance of ( R = c,t ):
Every local observer, regardless of the cosmic epoch, experiences the expansion such that one year of proper time increases the radius by one light‑year. This reflects the invariant nature of ( c ) in local measurements. - Epoch-Dependent Scaling:
When comparing measurements from different epochs, the evolution of the scale factor ( a(t) ) must be taken into account. A radius measured in the early universe is “rescaled” to produce the corresponding proper radius today. - Preserving Relativity:
Since the constancy of the speed of light is maintained locally and the scaling transformation is a well-established part of the FLRW metric, this hypothesis aligns naturally with Einstein’s theory of relativity. It offers a novel perspective by explicitly linking cosmic time with the radius of the hyperspherical universe.