### An introduction into relativity

There is a point made by Bell in the remarkable paper "How to teach special relativity" that it is useful to teach, together with the usual Minkowski spacetime interpretation, also the classical Lorentz ether interpretation. I think this should include also an introduction into the Lorentz ether interpretation of the Einstein equations of GR, as I have argued in my paper "About an ether interpretation for the Einstein equations of general relativity". I think, this deserves to be worked out, and I have started such an attempt to teach relativity by teaching above interpretations. The actual version of this introduction is: " Lorentz Ether or Spacetime? An Introduction to Relativity" [pdf]". (The part about special relativity [html] is available separately.)

An aspect of the "twin paradox" is examined: It is wrong that it is somehow the acceleration which creates time dilation.

### Problematic aspects of relativistic physics

Here I will collect some points where I'm critical of some aspects of relativistic mainstream physics. To clarify: special as well as general relativity have been, without any doubt, great advances of physics in comparison with pre-relativistic theories. And even if my own ether theory of gravity will be successful, this status will not be questioned: Instead, the Einstein equations of General Relativity would remain the natural limit $$\Xi,\Upsilon\to 0$$ of my own theory. This would define an ether interpretation of the Einstein equations of General Relativity.

• The way inflation theory is presented in popular (and not only popular) descriptions is a horrible misrepresentation, starting with the choice of the name "inflation", which, wrongly, suggests that it means a high expansion rate, instead of an increasing one.
• Hawking radiation is a prediction which fails because of the trans-Planckian problem: The derivation has to assume the applicability of the semiclassical approximation of quantum gravity, but uses this approximation in a domain there it makes no sense at all to assume that it holds.
• What is the problem with quantization of gravity? The main problem appears to be the insistence that quantum gravity has to be, like classical GR, a background-independent theory. Without this requirement, GR quantization becomes much more unproblematic.