Q: If all life or all existence comes from one origin what was it composed of and how did it get there? If you believe the answer starts with the big bang theory, there was matter to begin with it was just compressed and expanded so what would that matter have been and how did it get there in the first place? I understand that the big bang theory and the theory of evolution are explinations of two diffrent things. My question is about the origin if someone is to believe that the origin of life comes from a single place. There had to be some sort of matter to begin with in order to form a living organism. I did not say whether any theory or belief is correct or not. I'm asking if someone is to believe there is one origin what was that origin composed of and how did it get there. I was only addressing one answer I could have possibly gotten, and explaining that that would not fully answer the question either since that to answer the question that matter must have come from somewhere also.
A: Excellent questions. For the origin of matter - yes, the current best-accepted explanation for the beginning of the universe is the Big Bang (where everything was compressed into a singularity which then expanded rapidly, as you say). But this theory doesn't explain where that singularity came from; in fact, it doesn't even try. Sadly, science cannot currently answer that: the singularity's origin (if any) was obviously "before" our universe - and the laws of physics which science uses and understands do not operate "outside" or "before" our universe. So we cannot hypothesise what the conditions were. Though one thing we do know within our universe is that subatomic events can and do happen without cause: subatomic phenomena do just "appear" out of nothing. Since the singularity was just such a subatomic phenomenon (a point of zero volume), it is possible that it too happened "just because". For the origin of life - the original common ancestor which evolved into all life on earth, we actually have a slightly better idea (though the field - "abiogenesis" - is still hotly-debated and controversial). We have a pretty good idea of what the conditions on pre-life earth would have been like, and experiments (most famously the Miller-Urey experiment) have shown that those conditions are capable of forming short biological molecules (oligopeptides, oligonucleotides, lipids, etc.). It is thought that one such molecule - probably a short RNA molecule - was capable of autocatalysis (making copies of itself, as RNA is capable of doing), and that this self-replicating molecule was the first "life". Read the wikipedia article on abiogenesis and the "RNA world" hypothesis for more information.