pforeman said:
Is red shifting of light from distant stars actually caused from them moving away from us, or is this a simplification.
Doesn't this break the rule of light always going the same speed.
Could the light rays be possibly lengthened because when the light left many yrs ago space was smaller, now it is bigger so the wavelengths are now, necessarily longer
Thanks for your help
Paul
The idea of "tired light" has been discredited, but it's unclear if it's the same idea that you're proposing in part two. See for instance the wiki
https://en.wikipedia.org/wiki/Tired_light. Basically, the theory as proposed by Zwicky made experimental predictions that were inconsistent with observations, which you can read about in the Wiki article. Whether or not your description is the same as Zwicky's is a question I can't answer, you might try more reading. If your understanding of your theory is detailed enough to make predictions, you can perhaps decide if this experiment falsifies your theory.
The idea the relative velocity causes red-shift in General Relativity is basically incorrect. General Relativity, the theory that actually predicts the red-shift in question, does not have an unambiguous way of determing the velocity of distant objects. I would point to Baez's et al paper, "The Meaning of Einstein Equation" as a reference on this point, though it may be too advanced for the thread.
I'll explain a bit more as simply as I can. The relative velocity between two objects at the same event in space-time is well defined. In order to compare the velocity of two objects that are not in the same event (same place in space at the same time), according to the theory, there needs to be a transport mechanism to transport the velocities to the same location, where they can then be compared.
Unfortunately, in General relativity, this transport process, called "parallel transport", depends on the path, so transporting the velocity of the distant object along two different paths can give two different results, as Baez et al points out in their paper
Note that with these rules, there is no problem at all with the velocity of light being constant and equal to c. For a beam of light and a material object / measuring instrument at the same place and time, the measuring instrument will always measure the velocity of said light beam to be a constant, equal to c. A purist might have some more to say about this, but this post is already too long.
General relativity can be concisely described as the geometry of space-time. Space time can be represented by a space-time diagram, so General realtivity can be described as the idea that space-time diagrams should be drawn on curved surfaces rather than flat sheets of paper. That's the simplest and not very complete answer I have to give some guide as to what General Relativity acutually has to say as a theory. I'd also like to make a bit of a push for being able to draw and interpret space-time diagrams as a fundamental tool for understanding first special, and to a limited extent as above, General, relativity.
