Consider the following hypothetical observations, some of which are real and some of which are fictional. For each observation, your job is to answer this question: If the observation were real, would it provide evidence for or against the idea that the universe is expanding? Sort each observation into the appropriate bin as follows:
Supports the expanding universe: all galaxies in the Coma cluster of galaxies have redshifted spectra, the measured rate of expansion is the same in all directions, galaxies 200 million light-years away move away from us twice as fast as galaxies 100 million light-years away
Contradicts the expanding universe: irregular galaxies outside the Local Group are moving toward us, spiral galaxies move away from us 10% faster than elliptical galaxies at the same distance, galaxy speeds are faster in summer than in winter
Neither supports not contradicts: the Andromeda Galaxy, a member of our Local Group, is moving toward us