Am I an atheist?

[MasterDebater]

Do you mean the Big Bang theory? If you read up on what the Big Bang theory says, I assure you it is very different from your somewhat childish (no offence) description.

None taken.

I tried to read A Brief History of Time but it didn't grab me though it did seem to suggest that the universe opened up into a space that wasn't there and that there was nothing in existence prior.

That isn't at all what the theory states, nor what Hawking was talking.

The big bang theory (The name is misleading and was actually created by someone trying to ridicule the early theory, it would be more adequately called the big expansion) states that all matter, energy, space and time in the universe was once condensed into a single force of energy with no spatial dimensions (infinitely small), it is dubbed 'The Singularity'. For reasons unknown this singularity expanded creating space and time as well as breaking this unified field of energy into the forces of nature (gravity, strong nuclear force, electroweak force, the electromagnetic force etc.) as well as space and time themselves which did not exist prior to this point in time.

So to state that it was an explosion into empty space is completely incorrect, space-time it's self emerged from the singularity.

Also there is no claim that 'nothing was there' prior to the big bang because the singularity was there, it is simply the universe as we know it that had a beginning - We have no way of knowing whether or not the singularity had a beginning or not and if it did, we have no idea what this beginning was. The mathematical theories at the moment work until 1x10^35th of a second but are unable to describe the nature of the universe prior to this time, mainly due to our current inability to rectify General Relativity and Quantum Gravity.

If you have any more questions about it feel free to ask.