Lets assume the big bang theory is fact. It happened . The entire universe as we think we know it emerged from a tiny dot that exploded. Now we also have the thesis of an accelerating expanding universe. Deductions then tell us that if this big bang really happened there ought to be an area in the cosmos that is now completely devoid of any mater what so ever. It seems to me that the proof of the big bang is find that incredibly empty space at the center of everything.