THE BIG BANG!!! The big bang is a scientific theory of the beginning of the universe. Its has been estimated that it happened 13.73 billion years ago. No one know what was there before the big bang but it may have been a universe like we are in right now but nobody knows. When the big bang actually happened it let losses an amazing amount of energy into our universe. The universe got bigger and bigger. And its still continuing to get bigger today. All the energy in the big bang caused a massive amount of light to form all over the place.
THE BIG CRUNCH The scientific belief of the big crunch is that the universe ends the same way as the big bang started the universe. The theory is that the universe expansion which is cause by the big bang, will not continue to expand forever. One day when the universe stops expanding our hole universe will collapse into its self. It will pull everything into it ,and turn into a biggest black hole ever!!
STEADY STATE The steady state theory is another alternative for the big bang theory. The steady state theory believes that the universe is expanding but it does not change its looks over time, because new matter is formed all the time to keep the density equal.