The first time I ever heard anything about this issue was during my junior year, high school astronomy class in 1985/1986. We discussed it as part of a discussion about the "Einstein synchronization convention". There isn't anyone, (that I've ever heard of), that would entertain that light would or could travel at a different speed in one direction vs any other direction without there being some sort of cause (like the presence of an Eather, for example). Meaning that if it isn't the same speed in every direction, there would be a particular direction that the light "preferred" to go due to whatever it was causing the difference in speed.This is not what is meant by the "one-way speed of light."
The one way speed of light not in a universe relative direction, or in an earthward direction, it's ANY direction, particularly the initial direction light travels when being measured.
The problem is that in order to measure it, we need the clocks to be synchronized, which requires the reflection of the light, which makes it impossible to know if the speed of light in the first direction is the same as the second, or if it's instantaneous, and the second pass, the reflection, is half of c.
One-way speed of light - Wikipedia
en.wikipedia.org
There was at least one guy who spent some energy on it. I totally forget who it was or even much of any details except a point being made about, if such a directional preference could be detected, it would form the basis of universal coordinate system in at least two dimensions. All moving objects could be classified in accordance with the degree to which it was moving with or opposed to light's preferred direction and also whether it was parallel vs perpendicular to the direction that light likes to travel in. That, in fact, may have just been an idea that my astronomy teacher came up with himself.
That however, hasn't really ever been the focus of the issue because there isn't anyone who gives any serious credence to the idea that light actually travels faster in one direction than in any other because there isn't any way, even conceptually, that a difference in the speed of light in one direction vs another could ever be detected. The issue is merely about the nature of light causing it to be physically impossible to measure the one way speed of light. As you say, you have to synchronize clocks and the information being communicated by the clock is itself traveling at the speed of light, etc. Because of this quirk of the nature of light and the speed of information forcing a round trip measurement of the speed of light, it is theoretically (i.e. conceptually) possible that light could be traveling at a different speed in one direction vs another but no one actually takes it seriously enough to believe that it actually does so and those few who have postulated it as a real possibility universally believe that there would be a cause for it and that therefore, as I said a moment ago, there would likely be a directional preference.
The only thing anyone ever needs to see in order to fully understand the issue is this excellent video...
Well, I can't tell if you see it yet or not, but I think I've proven that, by itself, stretching out the heavens is insufficient to explain the celestial events we witness. Something else is going on. Either God created the universe much longer ago than 7500 years, or God created stars in an already exploded state, or the Andromeda Galaxy (and several other, supposedly further away galaxies) are less than 7500 light years away, or some combination of those possibilities. No matter how you cut it, heavens stretching, by itself, doesn't get the job done.Which is why I don't think it's a good direction to go. But it is certainly a possibility.
And again, maybe the fact that God stretched out the heavens has something to do with it.
Clete
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