The universe appears "old", but it is still less than 10,000 years old

[orogenicman]

Yes it is, because there is only one observer, not two. The experiments for two-way speed of light measures the round trip speed of light between two points, hence the synchronization issue. This experiment eliminates that problem by only using one point of measurement. In other words, the starting and stopping point is at the same location, thus there is no synchronization issue. That they used mirrors to get the light back to the origin is irrelevant to the measurement because light reflecting off of a mirrored surface doesn't change velocity, only vector direction. That the entire apparatus rotates and they get the same results verifies the Michelson-Morley experiment. You should also read the last link.

The last link takes you to the same paper as the second link. The fact that the same location is used for emission and detection is irrelevant. If you shine a light onto a mirror and time how long it takes to get back to you, it is the two-way speed that is being measured. The light is going from point A (you) to point B (the mirror) and then back to A. It's a two leg journey. Adding more mirrors creates more points, not less.

The first paper is the more interesting one. It does actually test the one way speed, (which is nice) but the spinning holed discs do not remove the problem of synchronisation. It's still assuming an isotropic convention in regard to the photodiodes.

Any discussion over the one-way speed of light is not that it cannot be measured, but that some method must be used to assure that the clocks at each end of the measured path are "synchronized" The mirror discussed above is NOT point b because it isn't measuring anything. Point A and point B are the same (the origin). Thus, because the experiment uses only one clock to measure start time and end time, the measurement eliminates the problem of synchronization. But I see your point about the two overlapping because, by definition any measurement in which the light follows a closed path is considered a two-way speed measurement. Point taken.

Here are some thoughts. If the one-way speed of light and the two-way speed of light are assumed, for purposes of discussion, to be different, why then, when we conduct a two-way measurement, is the frequency the same in both directions? Why is there no shift, which there must be if the velocity had changed?

Moreover, for purposes of determining the age of the universe, why would we ever need to know the one-way speed of light? Since we are essentially always measuring the two way speed, and that velocity is verified by numerous independent research paths and theoretical calculations for well over 100 years, what's the point? How would the two-way speed of light negate the distances measured in the universe, particularly when those measurements depend ultimately on the standard candle, which is also well understood to depend entirely on the inverse square law, not the speed of light, and on the parallax of stars, which is also well understood? My point is that it doesn't, making warped one's argument that the age of the universe as determined using this measurement being wrong is superfluous. It isn't wrong. What's worse, he doesn't explain how such a "wrong measurement" could ever give us a number such as 10,000 years, or any other such fanciful number.