«For years, we know that the universe is full of ‘dark’ matter, even if you do not know its nature. Likewise, we know that the universe is afflicted with massive neutrinos exist and, essentially confirmed at CERN, there is a ‚Higgs’ background field in the universe. Fields and invisible particles exert forces on the visible matter. Therefore the question arises whether physically realizable inertial systems exist.
In physics, an inertial frame (from the Latin iners “idle, lazy”) is a coordinate system in which force free bodies move straight and uniform. Different inertial frames move relative to one another uniform and rectilinear. This also means that one must always make sure that there are no unknown forces if a system is to be an inertial frame.
The question whether there are inertial systems can, therefore, should be answered with a strict no. Thus, the basis of the theory of relativity is not satisfied in reality.
Because Einstein stated held firmly in his booklet “The Special and the General Theory” (Springer, 1988, pp. 102):
By showing the physical equivalence of all inertial frames, the theory of special relativity proved the untenability of the hypothesis of a stationary ether.
Realizing this, he formulated his first postulate:
Two observers moving with constant velocity relative to each other, observe the same physical laws. All inertial frames are equal in all conditions.
This postulate is therefore untenable.
But his second postulate is also invalid:
The vacuum speed of light for all observers is an absolute constant, it is independent of the light source and that of the observer.
If, as we have seen, there is no empty space, then a homogeneous distribution of matter in space is only a simplifying assumption physically. Thus in reality is the speed of light from the direction and the locationdependent and therefore a vectorial quantity. Thus also the speed of light is not independet of the speed of the light source and of the observer.
Conclusion: The theory of relativity is not practically realizable.»
Walter Killer, July 16th and August 1st 2012