Then there is dark matter

The universe evolves, growing in dimension.  Light remains the same but in flatter regions of space, dimensionality 1 while we have dimensionality 2, in these flatter spaces, the solutions to Schramm-Loewner are k=6, not k=12 (in non reduced form).  So the matter is primitive, the light  fewer bands but the same size spectrum, likely no quarks but primitive charge.  Most likely a magnitron type of electron orbiting the nucleus farther out.  The Nucleus may be  a two particle and orbits less separated. A lot more fuzzies.

Gravity is not infinite, and gravity terminates in these huge expanses of Lagrange regions between galaxies.  That is where the older universe lives. Its light would not survive a trip through dimensionality 2 free space, and emissions would be a dull glow.  Maybe thsi is the background radiation. Light from our world would mostly pass through it, as if it were glass.  But when that light emerged back into dimensionality to, it would undergo a disruptive red shift.

But we are evolving, and we are not doing it with complete central authority, but the older previous generation lives on and coexists. Its the same as big bang, just slowed down by 10e32 years, and still ongoing.  This is really what multiverse is about.

Carbon, oxygen and nitrogen do the same thing, they overlap two fourth order worlds.  It is possible because the number line is quite flexible and unused parts of it can be used as angle separators.