The answers that apply are the following:
The universe is continuing to expand.
A massive explosion caused matter and energy to expand and form the universe.
The cause of the big bang was dark matter and dark energy.
The Big Bang Theory is an attempt to explain how the vast universe began. It was made into conclusion through multiple formulas. According to this theory, the universe began from a singularity such as that of a black hole. Out of that singularity, came a massive explosion, hence the term 'big bang'. Because of this explosion, the expansion of universe began. Until this day, the universe is still continuously expanding, according to this theory.
