Watch fireworks. They have a big bang. If you’re talking about a theory that scientists came up with about the creation of the universe, you should ask the scientists that came to that conclusion. If you ask me, the big bang theory is one of many other theories that occurred simultaneously like string theory for instance. The proof has been in front of our eyes all of the time. We can use equipments and objects on the Earth to physically experiment with such as rocks, ropes and something that pops. Use them all in motion. A group of people can spin around grabbing a thick rope that attaches to 8 rocks to indicate the planets in our galaxy. What happens next is the rocks separating when the rope is let go. The explosion is like the rope made of electricity that has detached and that’s why the planets drift away from each other. It’s all about motion and relativity. The stars are like this electric rope in my example that are particles from the detachment after the rocks have separated from the rope hence the planets in motion. The bang is the rope of electricity that has passed through the rock hence the electricity on Earth. It took me a few years to come up with this idea.