I'm doing some research and am trying to determine whether the creation story of Genesis, chapter 1 (7 days-let there be light) is consistent with the Big Bang Theory. I am finding sources that contradict one another. I'd like to know if the Genesis story of creation is consistent with the Big bang theory solely from a Catholic point of view.
The Catechism of the Catholic Church has
Thus it may be seen that Catholic teaching, expressed in the Catechism, does not depend on the literal truth (or not) of Genesis 1. Other than a few brief words of literary analysis, it expresses no opinion — although St Augustine of Hippo certainly did. What is important is that Genesis 1 testifies that God created all that exists, and did so from nothing.
Although God is continually revealing himself and his methods, scientists have not reached the origin of creation, either by observation of the deep universe or by theoretical calculation. Even if one posits that the Big Bang was the means by which creation was effected, it is thought that everything emanated from a singularity: a point of infinite density and zero size — nothing.
128: Gen 1.1
Some Christians believe that the universe was created with apparent age, i.e., that it appeared fully formed, mature and complete, looking older than it actually was. For such Christians, the big bang is completely consistent because it is a description of how the universe appeared to have been created, not necessarily how it was created. The common argument against this position is that it makes God deceptive, but you would only be deceived if you first ignored God's revelation of how he acted.
A further explanation for this theory:
The universe God created has a few fundamental physical laws. One is the law of conservation of mass/energy: it is impossible for matter or energy to come into existence in the universe that did not exist before. (Ignoring quantum mechanics, in which case it would appear to come from other interactions, which we can detect now.) This is true even when God acts miraculously. When Jesus turned the water into wine the wine appeared much older than it really was. If you had tested it with today's technology you would have been able to detect the types of grapes it had been made from, the wood of the barrels it was stored in, the time it had matured. Jesus could not have made excellent wine that wasn't old, because young excellent wine can't exist.
The simplest miracle God could do is create a single particle, such as a photon. But God couldn't create a photon in a way in which the photon would have appeared to have spontaneously come into existence. The photon would appear to have been travelling in a straight line for all time before.
There is only one fully stable state for the universe: a singularity. The universe cannot appear to be infinitely old. So when God created the universe it must necessarily have appeared to come from a singularity. In a sense, the big bang is inevitable.
The 1909 Pontifical Biblical Commission said:
See this for more info. So for Catholics there is no inconsistency.
Pope Pius XII spoke of the compatibility of the Catholic faith and the Big Bang theory in his 22 November 1951 speech to the Pontifical Academy of Sciences. (Unfortunately, I don't know of an English translation of it, but this machine translation isn't too bad.)