It is indeed too hard to answer that question. Is that the main reason why you no longer believe that someone created all those?

Since you are talking about science, has science able to answer that questions as well? Atheists usually says that in the feature science will do unfortunately it is not on our timezone so how sure they are?

Now let's try to reverse your question. Lets say there is no God who created the Big Bang then how do you think it happened? By accident? Well atheist usually says that but for my common sense there should always be a being who or that is responsible for all of these