## The Meaning of Special Relativity in a Wave with Medium (4)

Does solution 3 look familiar? The formulas are exactly the same as that of Special Relativity.

How were the formulas of Special Relativity obtained?

Einstein first assumed that light follows the rule of relative motion, and used a round trip. That is where the c+v and c-v comes from. And later, he assumed that light follows the rule of absolute motion and propagates in all reference frames at the same constant speed of c.

We got the same formulas just because we followed the same path taken by Einstein.

With this knowledge in mind, it is easy to see that the light clocks used in the introductory books on Special Relativity are all fake ones. The authors took the 90° case just because of its similarity in mathematical form. The light beam of a correctly mounted light clock should be parallel to the spaceship’s direction of movement.

In our example here, the broken formula does not mean that the river is not allowed to run faster than the swimmer. It only represents the fact that in the case of v ≥ c, the swimmer will never have a chance to reach upstream. Because an average speed can not be obtained, any effort trying to adjust this average speed to c is certainly to fail.

Due to the same reason, Special Relativity does not imply that the speed of light is the speed limit in the universe, even if Special Relativity is correct.