Shape of Universe - What would a very long stick do

[Tanelorn]

Page 40 here is what my understanding of superluminal velocities is based on:
http://www.mso.anu.edu.au/~charley/papers/LineweaverDavisSciAm.pdf

I mentioned red shift because it shows that things are receding faster the further away they are and extrapolating from this to superluminal velocities.

 

[PeterDonis]

Page 40 here is what my understanding of superluminal velocities is based on

This is a pop science article. It's not a good reference, even though it's written by scientists. "Pop science" does not mean a non-scientist wrote it. It means that whoever wrote it, scientist or not, was not trying to give you an actual predictive model that you can reason from to get valid conclusions about the physics. If you want to learn about the actual physics involved in cosmology, you need to use sources that are actually trying to give you a valid predictive model. The Ned Wright tutorial can give you a start, and gives references that can get you further.

I mentioned red shift because it shows that things are receding faster the further away they are

But that's not what the red shift "shows". The red shift by itself does not tell you how far away something is, and it only tells you "how fast it is receding" if you interpret it as a Doppler shift, and that interpretation is problematic when spacetime is curved.

 

[Tanelorn]

Wow, thanks Peter. I was using that document to clear up other populist ideas and I thought I now had things much clearer now!