Redshift

The main evidence for the expansion of the universe is something called redshift. Redshift is the tendency for the light of far away objects to be composed of wavelengths at the red end of the spectrum.

Hypothesis 6

In Matty's Paradigm we believe that the universe is enclosed in a crystalline sphere called the firmament, so it can't be expanding. Obviously there's some other explanation for the apparent redshift of stellar objects.