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

[orogenicman]

Here is a method for determining the one-way speed of light:

http://www.sciencechatforum.com/viewtopi...=2&t=23451

Take two photon detectors. These can be arbitrarily thin - less than a millimeter if necessary. Take the two detectors and place them side by side. From each detector take a cable of a convenient length. Put both of those cables into fast electronics (a modern digital oscilloscope will work just fine).

Fire a light pulse through both detectors. Since these two detectors are adjacent to one another, the transit time from one to the other is of order (1 mm)/(speed of light) = (1 x 10-3 m)/(3 x 108 m/s) = 3 x 10-12 seconds. If sub- 3 picosecond speed is needed, there are ways.

Using your oscilloscope, you can calibrate your cables to establish what "simultaneous" means. In the abstract, the cables can be of identical length. This means that the signals from the two detectors will arrive simultaneously at your oscilloscope.

Now move one detector far away...maybe 1000 feet. Do not disconnect the cables, so you have identical conditions. Fire the light pulse (use a laser) through one detector to hit the other. The signals from the two detectors will transit the cables and hit your oscilloscope at a single spatial point. Since you have already established that the transit time in the cables of both detectors are identical, the only difference between the signal arrival time at your detector is the transit time of light from one to the other. If you have measured the distance exactly, you can then determine the speed of light by distance over time.

If you do not want to measure the distance between the two detectors, you can verify the isotropy of space (and consequently, the identical nature of the 1-way speed of light). First do as I said, and fire a laser that first hits detector 1 and then hits detector 2. Record the transit time seen in your oscilloscope. Now have a laser pointing in the opposite direction, hitting detector 2 and then detector 1. Again, record the transit time.

Since the distances are the same, and the only difference is the direction in which the light is travelling, you can establish that light going one way takes the same speed as the other way.

I believe that within the uncertainties of your equipment, this detector configuration will establish that the speed of light is the same in either direction.