What went bang to start everything?
There isn't anything in currently accepted mainstream physics that describes the process leading up to the "big bang." So, the answer to your question will involve "exotic" theories like Ekpyrotic theory and other forms of the cyclic universe explanations, and others. But the truth is that science can't answer your question today, that why we're still doing research.
Sometimes, the phrase "big bang model" makes people think of an explosion, or a "bang," that created the universe. It should be noted, however, that the big bang model does not necessarily mean this, but rather is a model of cosmology that develops such that the universe was smaller in the past and has increased in size from then-- i.e. that the universe is expanding.
As the above poster says, we currently do not know what preceded the "big bang", or what happened in the time immediately proceeding the "big bang," and so cannot possibly say what happened. Many theories have been developed, but cannot and have not yet been proven since there are currently no accelerators that are probing high enough energies to look into the first 10^(- something big) seconds of the universe. Whether such accelerators would help prove the theories is another question, but they would, I imagine, be of some use. Because of this, the very early universe (as in the time before the "Grand Unification Epoch," where all four forces were of equal strengths) is often referred to as a "theorists' playground!"
Please note: do not feed the troll. Use the REPORT POST button.
Now back to our regularly-scheduled program.
Separate names with a comma.