Strange

It is very well established that photons always travel at c, relative to any source or any observer. So they do not travel at 2c relative to anything. No. See above. Why? This seems like a completey arbitrary change. And basic dimensional analysis shows it to be wrong (as you will see if you include the units in your calculation). If by "less" you mean with less mass, then there are no particles with less than zero mass. (There is absolutely no reason to think that the mass of the photon is not zero.)

I will use exactly the same level of evidence and logic that you do to make my case. Ready? OK: you are wrong. https://en.wikipedia.org/wiki/Apophenia

Why would amplitude imply resistance? Resistance would cause amplitude to decay (as the energy in the wave was converted to heat energy in the medium). That sounds about right (although not just any changes). In practice, no, because there is matter and energy in the universe. But in principle, you could have a universe with space-time but no matter or energy.

His description is so confused, I don't think it could be described as "accurate". It is roughly along the right lines with a few errors and/or incomprehensible sentences. His first sentence is wrong (and is contradicted by what he says later). I would ignore him and focus on what Wikipedia (and the texts it references) says.

No. They are philosophical views so the evidence doesn't distinguish between them. All I mean is that the mathematics of the theory makes predictions. Experiments make measurement which are compared with those predictions. If the measurements match the predictions then the theory is working. If you are a substantialist (not a word I have ever come across before) or a relationist (whatever that is) or an idealist or a realist or an orthodox pastafarian doesn't make any difference as to whether the measurements match the theory.

Probably not. The cost of being a realist is that you have to keep adjusting your view of what reality is when theories change.

It just means that the predictions made by the theory match the measurements we make.

That is correct. Yes. But any attempt to define this in a rigorous way will be full of exceptions and special cases, and will not cover all cases. There are many other things that cannot be rigorously defined in this way: art, religion, pornography, consciousness, etc. All abstract concepts that we recognise when we see them but find it impossible to define.

Because you insist this medium must be made of some sort of tangible material. This contradicts all the evidence. But if you are happy to accept the (intangible) field as the medium, then the discussion is over.

If mike would only accept the fields as the "medium" this would have been over long ago.

In our industry we make use of holes as charge carriers. It is quite hard to argue that holes "exist"

Not necessarily. Not necessarily. Not necessarily. Not necessarily. Not always. So it seems like you have invented some nonsense rules that you think the universe works by, and then you wonder why the universe works that way. Answer: it doesn't.

Do you have any evidence that is the case? It sounds implausible to me. What do you mean by 'a "sterile" and appeared alone Universe' ? And why would that be relevant? I still don't know what you mean by your original question. Are you asking if it was created? If so, there is no evidence that the universe was created (or started in any other way). Are asking if it was created alone; i.e. the only universe? In which case, it is the only one we know of. We can't really speculate beyond that. Or are you asking if the universe created itself; i.e. without outside help? In which case, not only is there no evidence it was created, there is even less evidence that it was created by "external forces". I can't see why. What does it make you suspect?

I don't think there is one. I am a "naive realist" by inclination so I tend to think that things like electrons and spacetime are real things that are described by our theories. But I know that opinion is silly and completely irrational.

It is measuring something we call electricity. I have no idea what that is, though. It might be something to do with electrons, if they exist rather than just being a useful model ...

The trouble is, it isn't always clear what is being measured. For example, it can be argues that the Pound-Rebka directly measures the effects of the curvature of space-time. Or, does it just measure "something" that we describe as the curvature of space-time. (Which is back to the question in the OP).

I would say it is more of a philosophical concept. By which I just mean that one has to define (precisely) what one means by the word "real" before the conversation can actually be useful. On another forum, someone has defined "real" as meaning "you can hit it with a hammer". By this criterion, space-time is not real, even if the mathematical model accurately describes something that exists!

As Markus says, it is not that simple. The combination of velocity and gravitational potential might lead to that result. Or might not. It depends.

Even if it were "only" near the speed of light, it would have destroyed the whole Valley of Elah. https://what-if.xkcd.com/1/

Looks like someone who appreciates your "modest proposal" has removed your negative vote.

Apparently, the original meaning of "close minded" (15th C, if I remember correctly) was someone who kept things to themselves (i.e. kept their thoughts close).

And in a thought experiment you work out what would actually happen, not decide on the impossible conclusion you want and then try and make up arguments to support that. What is the point of this thread now?

That is according to a model that you think is inadequate because it doesn't include a medium for gravity. Your new model may produce a different result for that question.

There are two possible effects here. There is the time dilation due to the moon (or a satellite) being at a different gravitational potential than the observer on the surface of the Earth. And there is time dilation due to the relative speed between the moon (or satellite) and the observer on the earth. Both of these have to be allowed for by GPS receivers, for example. I don't think acceleration per se has any effect (other than resulting in a different relative speed).

I think that is still acceleration. Because the moon is in free fall, it is not actually accelerating. For example, if you were in orbit or free fall, you would feel no forces acting on you, therefore you are not accelerating. If you are not following that geodesic because, for example, you are standing on the surface of the Earth, then you do feel a force and (counterintuitively) you are accelerating - even though you are not moving! I'm not sure where the weight loss idea comes into this ...