We can say about a mention is scientific if we can analyze and repeat that mentioned process.
Our theory of the origin of the world is the big bang theory, which say that there was the absolutely nothing, and sometime occured something which explode this nothing (simplify summery). We are not able to analyze this process, and we have never can explode the absolutely nothing.
I see that we are living in an expanding universe and the opposite of this expansion means that one starting point is needed. But it is just a theory not an scientific mention (even so every scientist talk about this theory like a fact).
So simplify I would you like to ask that what evidences attest to the big bang theory is more than a simply theory?