Can Gravitational Forces alone Account for Galaxy Formation in a Steady State Universe?

Steady-state cosmology requires galaxy formation at the present epoch. It is shown that, unless matter is preferentially created in the presence of existing galaxies, a stationary galaxy cannot gravitationally attract a sufficient amount of matter from the extragalactic medium to double its own mass within a time T /3, where H = 1/ T is Hubble's constant. An approximation shows that a moving galaxy is also incapable of accreting extragalactic matter at this required rate. By summing over the contributions of all galaxies, one concludes that gravitational forces alone cannot bring about galaxy formation at the required rate if matter is created uniformly throughout a steady state universe. If the steady state theory is to survive, one must postulate that either (1) creation is a markedly localized process, or (2) there exist forces, other than gravity, which can lead to galaxy formation.