Relativity is much more some sort of mysticism than it is a matter of physics.
Relativity has no real physical meaning, it is just for inventing such things like black holes. No one has ever proved the existence of such black holes.
Special relativity is derived from the misunderstanding that light would be a wave.

I don´t think that light is a wave, light consists of particles where every single particle is able to oscillate in some way. The Michelson experiment is easily explained by such particles. Other properties of light may be anlogoues to a wave but it is not the same. The transfer of light like a beam alone rules out that light is a wave. A wave in water does not propagate like a beam.
The diffraction of light is completely different from the diffraction of a wave in water. Light is travelling like a beam and only after a gap diffraction occures. The wave in water always tries to propagate in all directions, this is the same as what is called diffraction after a gap. It is the transfer of movement from particles of water to particles of water. The diffraction of light occuring only after a gap must be caused by something, it could be caused by infrared radiation for example or something similar.
There is no effect of light which is exactly the same as the behaviour of a wave in water.
Special relativity is the attempt to describe something as a wave where no wave exists. For this reason the whole universe has to distort for every particle of light depending on the direction this particle is travelling. This makes no physical sense, it is just a mathematical castle in the air.
A mathematical description of a theory is a precondition for a theory but it cannot give proof that a theory is right. Mathematics is able to quantify but it cannot qualify something.

The same can be said for the so called general relativity. Even if it were possible to describe gravitation by some sort of geometry it does not make physical sense. Apart from this a bended space implies the existence of an absolute space which contradicts the claim of the theory of relativity that everything is relative.
But that there exists an (absolute) space is obvious anyway.
 

Furthermore relativity is based on at least inaccurate defined mathematics.
It does not make sense to define negative numbers. If one assigns a negation sign to a number a system of rules is obtained. But it is quite a difference if one thinks that there "exist" negative numbers or if one is aware that there are just a number of rules. If there exists negative number one would expect that this system works always, but if there is just a system of rules one does not expect that this system works always. And that is the difference. When we speak of negative numbers we expect that this system works under all circumstances but that is not the case. The so called imaginary numbers and the complex numbers respectively are just some kind of mark numbers. This numbers become necessary because of the unfounded definition of negative numbers.