Here’s a passage from Hans Küng, The Beginning of All Things: Science and Religion (Grand Rapids and Cambridge: Eerdmans Publishing, 2007), translated by John Bowden from Hans Küng, Der Anfang aller Dinge: Naturwissenschaft und Religion (Munich: Piper Verlag, 2005), 55-56:
When around the middle of the twentieth century an attempt was made in apologetic Christian writings to identify the point in time of the Big Bang with a divine creation of the world, non-Christian Marxist scientists, according to the German astronomer Otto Heckman, “disturbed about these theological tendencies, decided simply to put a stop to their cosmological source: they created ‘steady state cosmology,’ the cosmology of the expanding but unchangeable universe.”
This theory was put forward above all by Fred Hoyle (Cambridge, 1948/49), who in 1950 in a radio broadcast invented the term “Big Bang” almost as an insult. This theory claims that there is an eternal universe in equilibrium that extends without a temporal beginning and a temporal end and in which the density of matter remains the same as a result of the constant production of matter. But the thinning of matter as a consequence of continuous expansion must be balanced by a spontaneous production of matter. However, this contradicts the second law of thermodynamics, the entropy principle of the irreversibility of physical processes: without the introduction of energy to maintain the structure, a system always tends toward a state of higher disorder (for example, flowers put in a sealed container will die).
When I was in high school, so far as I knew the Big Bang and a small handful of roughly similar steady state cosmological models were both still viable options and subjects of debate. Since then, things have obviously changed. Nobody, or virtually nobody, advocates a steady state cosmology any more.