Please NOTE: "For example, a question that proposes a new concept or paradigm, but asks for evaluation of that concept within the framework of current (mainstream) physics is OK."
And: "Similarly, a wrong answer that makes false statements but claims to work within the bounds of a mainstream theory is also allowed."
See: Is non-mainstream physics appropriate for this site?
The question is indeed in the realm of mainstream science: It's asking about the existence and/or evaluation of a model that explains mainstream observations, such as expanding space and the big bang--but in a slightly different way. Please actually read the question...
I thought of a hypothetical explanation of cosmological redshift. Namely, the light's reference frame (space) is expanding but the distance between objects, galaxies, for instance, is not.
It's just a thought I had. I'd like to know if anyone has explored or refuted the idea. I've never heard it mentioned before.
To re-summarize the idea: Space is expanding but the universe is not, i.e., space expands without changing the distance between objects.
EDIT. To avoid causing confusion, I thought I'd point out, it might seem strange to have expanding space that does not cause objects to move apart, there are, however, at least two ways that this might happen:
As space expands, all objects move towards one another in just such a way that expansion does not cause an increase in distance. Inward motion/contraction cancels out the increase in distance.
Matter and light have two distinct reference frames.
NOTE. Also please note, I'm not talking about the past expansion of the universe from extreme density after the big bang. This is about the macroscopic recession of large objects long, long after the big bang. In other words, the cosmological redshift we see today.
Remember, this is just a fun thought exercise.