Question

The most-accepted theory for the origin of the universe is called the ? . This theory suggests that our universe explosively expanded into existence from a small, dense, hot singularity.

Answer 1

I think it's the big bang theory!

Answer 2

The big bang theory is what you mean.

According to this theory in start there was no system of earth and all planets were combined. Then there was explosion due to which planets originated and the system of earth and universe started.