Spoonfed wrote:
Jim Black wrote:

That's why the velocity of galaxies away from us is proportional to
their distance (until relativistic effects kick in, and their relative
velocity compared to us becomes ambiguous).

Relative velocity does not become ambiguous when relativistic effects
kick in.

I think the crux of the disagreement is that he's talking about general
relativistic effects, while you're talking about special relativistic effects.

He is correct. You would be correct if the universe were accurately
described by special relativity at cosmological scales, but it's not.

-- Ben