The Principle of Contingent Causation: The Impossibility of Infinite Regress.

[Bucky Ball]

This is from the AMNH: "The Big Bang was the moment 13.8 billion years ago when the universe began as a tiny, dense, fireball that exploded. Most astronomers use the Big Bang theory to explain how the universe began. But what caused this explosion in the first place is still a mystery."

The Big Bang Theory say nothing about the beginning of anything. 

The "bang" was the expansionary epoch. 
The theory says that *something* at very high density and temperature "banged". 
*Nothing* is not at very high temperature and density. Something was already there, and in a certain described physical state. 
The actual theory says nothing about a "beginning" of anything. 
Fundy Christians have MISCHARACTERIZED the theory to serve their own ends. 
The first question is not what caused the ecpansion, not the "explosion", but what was at high temperature and density that expanded. 
Sorry. Try harder.