Which God.?. The big bang is a Hindu mental figment.. In an almost endless array of convoluted cycles.. You know, the religion that proudly produced the caste system.. that one.. from an area where the Hindu and Muslim religions dominate..
Hindu and Muslim mind you.. My dog has more morality than the Hindu and Muslim religions have in their back hooves..
You say "which God"... and seem to argue that because we cannot know "which God"...and because there are some interpretations of "God" with which you disagree...that there is no God?
The Big Bang is compatible with a number of religions, not just Hinduism (one religion in which the current theories are a bit of a stretch, actually). Ditto with Islam.
The Big Bang, as a scientific theory, is not based on any religion. While some religious interpretations conflict with the Big Bang story of the universe, there are many other interpretations that do not.
This from Wikipedia (not a complete or reliable source, but food for thought here)
http://en.wikipedia.org/wiki/Big_Bang
The following is a list of various religious interpretations of the Big Bang theory:
A number of Christian churches, the Roman Catholic Church in particular, have accepted the Big Bang as a description of the origin of the universe, interpreting it to allow for a philosophical first cause. Pope Pius XII was an enthusiastic proponent of the Big Bang even before the theory was scientifically well established.
Some students of Kabbalah, deism and other non-anthropomorphic faiths concord with the Big Bang theory, for example connecting it with the theory of "divine retraction" (tzimtzum) as explained by the Jewish scholar Moses Maimonides.
Some modern Islamic scholars believe that the Qur'an parallels the Big Bang in its account of creation, described as follows: "Do not the unbelievers see that the heavens and the earth were joined together as one unit of creation, before We clove them asunder?" (Ch:21,Ver:30). The claim has also been made that the Qur'an describes an expanding universe: "The heaven, We have built it with power. And verily, We are expanding it." (Ch:51,Ver:47). Parallels with the Big Crunch and an oscillating universe have also been suggested: "On the day when We will roll up the heavens like the rolling up of the scroll for writings, as We originated the first creation, (so) We shall reproduce it; a promise (binding on Us); surely We will bring it about." (Ch:21,Ver:104).
Certain theistic branches of Hinduism, such as in Vaishnavism, conceive of a theory of creation with similarities to the theory of the Big Bang. The Hindu mythos, narrated for example in the third book of the Bhagavata Purana (primarily, chapters 10 and 26), describes a primordial state which bursts forth as the Great Vishnu glances over it, transforming into the active state of the sum-total of matter ("prakriti"). Other forms of Hinduism assert a universe without beginning or end.
Buddhism has a concept of a universe that has no creation event. The Big Bang, however, is not seen to be in conflict with this since there are ways to conceive an eternal universe within the paradigm. A number of popular Zen philosophers were intrigued, in particular, by the concept of the oscillating universe.
"My dog has more morality than the Hindu or Muslim religions"..............But at least the Hindus are not trying to cut your throat.