— a review of two cosmology papers presented at the International Conference on Creationism in 2018 (to be published in *Journal of Creation*)

## Introduction

In 2001 Jason Lisle (under the pen name Robert Newton) introduced the idea of Anisotropic Synchrony Convention (ASC) into the discussion amongst biblical creationists to solve the starlight travel-time problem.^{1} The ASC is a convention on clock synchronisation, or put another way, the conventionality of the simultaneity of distant events in *spacetime*.

This topic is relevant to the discussion of the creation of the stars in the universe on Day 4 of Creation week 6 thousand years ago. The ASC posits that an event occurs when an Earth observer sees, or could have seen, the event happen. And Lisle proposed that the ASC is the language used in the Bible. As such it leads to the initial simultaneous^{2} creation of all stars in the universe on Day 4, where, in principle, the event is timestamped^{3} as occurring when the starlight from all stars arrived on Earth for the first time. This means there is no light travel-time problem because the events were seen to occur (on Earth) simultaneously (or at least, within the period of one Earth day, that is, on Day 4). Therefore, there is no light travel-time problem.

In 2010 Lisle strengthened his original arguments with a discussion of the past light cone and Special Relativity.^{4} In that paper he introduced the ASC model, a model that uses the ASC. And his ASC model makes testable predictions.^{5}

Lisle also carried further the notion of the one-way speed of light. Since the one-way speed of light cannot be measured it really has no physical meaning in the universe.^{6} Thus there is a free choice. And by Lisle’s choice of the ASC it follows that the incoming speed of light is infinite, and thus the outgoing speed must be ½ *c* (where *c* ≡ 299 792 458 m/s is the canonical isotropic—i.e. two-way—speed of light that we are very familiar with).^{7}

Many people, biblical creationists included, have expressed disbelief, concern, and other emotions over the concept of the one-way speed of light being any different from the usually assumed isotropic speed *c*. Nevertheless it is important to note that concepts around the one-way speed of light are based on real physics.

The choice of a timing convention in no way affects any underlying physics. The physics is always the same no matter what convention one may choose.^{8} Einstein chose a value of the clock synchronisation parameter, known as the Reichenbach synchronization parameter (ε), in his equations for Special Relativity that *defines *the one-way speed of light as being equal to the two-way speed.^{9} Any value for the parameter ε between 0 and 1 may be chosen. Nature itself does not choose, nor impose any requirement on its value within this domain. The parameter represents our free choice of a timing convention. Hence we are free to choose any value of the Reichenbach synchronisation parameter ε, provided it is between 0 and 1. Einstein chose ε = ½ (ESC) and Lisle chose ε = 1 (ASC). Choosing a value for this parameter is in no way dissimilar to a choice of a different coordinate system. And regardless of which coordinate system one may choose the underlying physics is unaffected. What is different is only how we represent the physics in the different coordinate system. The equations of motion may be more complex in one coordinate system than in another but in all cases the physics is unaffected.^{10}

Thus no amount of appealing to Maxwell’s equations (derived pre-Einstein)^{11} or any other well-known physics can refute the notion of free choice for the one-way speed of light, or more precisely, the conventionality thesis of distant simultaneity.